Category: NIWA

Source: NIWA – National Institute of Water and Atmospheric Research

NIWA gathers information about fishing practices and the catch of an estimated 600,000 people who participate in recreational fishing every year. Interviewers will be at boat ramps along the north-eastern coast of the North Island, as well as parts of the west coast and some areas of the South Island. 

The project, led by NIWA Fisheries Scientist, Dr Jade Maggs, recruits interviewers who are often passionate fishers or members of local fishing clubs.

“We would just like to know a little about what you caught, and how you caught it. All information collected is kept private. The interviewers are not there to enforce the law, but only to collect scientific information. It’s completely voluntary and we don’t share people’s secret fishing spots.” 

Interviewers will approach people returning from a day’s fishing, enquiring about how many and what kind of fish they’ve caught, where they’ve been, the bait they’ve been using and how long they’ve been out.

NIWA Chief Scientist Richard O’Driscoll says it is really important that we know how many fish are being taken out of the ocean.

“This includes the recreational catch, which in some areas is as high or higher than the commercial take for species like snapper and blue cod. Our interviews, with the help of recreational fishers, provide the information needed for effective management of inshore fish stocks.”

These surveys are a vital part of NIWA’s research on recreational fisheries for Fisheries New Zealand. 

Fisheries New Zealand Principal Scientist Ian Tuck says that this research provides an important source of information about recreational fishing.

“We’ve had boat ramp surveys since the early 1990s – it’s one of the ways we get data on recreational fishing activity. This complements other research like the National Panel Survey, which is our largest recreational fishing survey, and area-specific surveys where more detailed information is needed, such as sampling of catch during the recent recreational pāua season in Kaikōura. The interviewers will be asking fishers about their catch, and this information will go towards stock assessments and informing fisheries management settings, such as catch and size limits.”

This year, NIWA are also collecting data on the number of snapper being caught and released in the recreational fishery. This follows on from an experiment last year, which looked at the survival rates of recreationally caught snapper that are released back to the sea. The new data collection initiative will involve volunteer fishers taking measuring mats and information sheets out on their fishing trips to record the size and numbers of snapper caught, as well as information about how deep they are caught and how they are hooked. 

More information can be found here.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Meagre rainfall totals of less than 10 mm were observed in much of the North Island in the past week.
• Pockets of rainfall totals of 10-20 mm were observed in the eastern and lower North Island.   
• This resulted in moderate soil moisture decreases in a majority of the North Island, although some western regions observed large soil moisture decreases.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in southern Waikato and western Wellington, while the wettest soils for this time of the year are found in Cape Reinga and parts of Gisborne and northern Hawke’s Bay.
• A hotspot is now in place in coastal Manawatū-Whanganui and the Kapiti Coast.
• As of 12 December, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Wellington.

South Island:

• Rainfall amounts of 30-70 mm were generally observed in the West Coast in the past week, with 100 mm or more in Fiordland.
• Much of northern Canterbury and Southland observed amounts of 15-30 mm, but meagre rainfall was observed in the upper South Island along with interior and South Canterbury.
• This resulted in small soil moisture decreases in much of the South Island in the past week, although small increases were observed in northern Canterbury and Banks Peninsula.
• The driest soils across the South Island, when compared to normal for this time of the year, are found in parts of Marlborough Sounds and western Southland, while the wettest soils for this time of the year are found in the upper West Coast and northern Canterbury.
• In the past week, the previous hotspot located in Banks Peninsula dissipated, the hotspots in Marlborough Sounds and Nelson remained in place, while conditions remained near hotspot criteria in South Canterbury, parts of Otago, and Southland.
• As of 12 December, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Wellington, Tasman, Nelson, Marlborough, North Canterbury, Banks Peninsula, South Canterbury, Otago, coastal Southland, and Stewart Island. Very dry conditions are now located in southeast Otago.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 12 December, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Wellington, Tasman, Nelson, Marlborough, North Canterbury, Banks Peninsula, South Canterbury, Otago, coastal Southland, and Stewart Island. Very dry conditions are now located in southeast Otago. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• This weekend (16-17 December) will be mostly dry, although some showers will affect Wellington and the western North Island.
• Monday and Tuesday will have a better chance for showers and isolated thunderstorms, particularly in the central North Island.
• High pressure will then bring generally dry weather late next week. 
• Weekly rainfall totals will again be meagre in many regions, especially in the upper North Island and east coast where amounts may be less than 10 mm. Pockets of 10-20 mm are possible from Taranaki to Wellington.
• Due to the expected rainfall in the next week, moderate soil moisture decreases are again likely in the upper and eastern North Island, with minor decreases possible in western regions.
• The current hotspot in coastal Manawatū-Whanganui and the Kapiti Coast may not change substantially in the next week, while a new hotspot may form in parts of Auckland.

South Island:

• The upper South Island will see some rain on Saturday, with additional heavy rain for much of the West Coast on Sunday (17 December).
• High pressure will then provide generally dry weather from Monday to Wednesday (18-20 December).
• Another front may bring moderate rain to the western and lower South Island late next week.
• Weekly rainfall totals of 70-100 mm are possible in the West Coast, but much lighter amounts of 20 mm or less are expected east of the Alps.
• Due to the expected rainfall in the next week, soil moisture decreases will be likely east of the Alps, with smaller changes likely in the upper South Island.
• The current hotspots in Marlborough Sounds and Nelson may strengthen slightly in the next week, while new hotspots may form in parts of the lower South Island.  

Long-term outlook (through mid-January):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios both favour widespread drier or much drier than normal conditions across both islands through mid-January.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still favoured in the upper and eastern North Island, although western New Zealand shows a chance for above normal rainfall in the wetter scenario.
• Very dry soil conditions could affect large swaths of both islands in the drier rainfall scenario.   

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Rainfall totals of 25-60 mm were observed in much of the upper half of the North Island in the past week.
• However, much of the lower North Island received lighter amounts of 20 mm or less.   
• Particularly meagre rainfall was observed in Wairarapa.
• This resulted in small to moderate soil moisture increases in the upper North Island, while decreases were observed in the lower North Island.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in western Wellington, while the wettest soils for this time of the year are found in the Far North and parts of Gisborne and Hawke’s Bay.
• While no hotspots currently exist in the North Island, a new hotspot is close to emerging along the Kapiti Coast.
• As of 5 December, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Wellington.

South Island:

• Rainfall amounts of 50-100 mm were generally observed in the West Coast, Tasman, and parts of Marlborough Sounds in the past week, with pockets up to 150 mm in higher terrain.
• Elsewhere in the South Island, light rainfall amounts of 15 mm or less were generally observed.
• This resulted in at least minor soil moisture increases in the West Coast, Tasman, and Marlborough Sounds, while minor decreases were generally observed elsewhere.    
• The driest soils across the South Island, when compared to normal for this time of the year, are found in parts of Marlborough Sounds and western Southland, while the wettest soils for this time of the year are found in Tasman and Fiordland.
• In the past week, the hotspot located in Marlborough Sounds remained in place, while new, small hotspots emerged in Nelson and Banks Peninsula. Conditions are also approaching hotspot criteria in South Canterbury and parts of Otago and Southland.
• As of 5 December, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Nelson, Marlborough, North Canterbury, Banks Peninsula, South Canterbury, and interior Otago.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 5 December, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Wellington, Nelson, Marlborough, North Canterbury, Banks Peninsula, South Canterbury, and interior Otago. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• After a generally dry Saturday, a weakening front will bring showers to the island on Sunday afternoon and Sunday night (10 December), followed by isolated showers on Monday.
• Additional showers will be possible on Tuesday and Wednesday (12-13 December), but then dry weather returns late next week.
• Weekly rainfall totals of 15-30 mm are possible in the lower and eastern North Island, but meagre accumulations of 10 mm or less are expected elsewhere.
• Due to the expected rainfall in the next week, moderate soil moisture decreases may occur in the upper North Island, with minor decreases possible in the east and west.
• There is a small chance that a new hotspot may form in western Wellington in the next week.

South Island:

• A strong cold front will bring heavy rain to the West Coast from Saturday afternoon through Sunday morning (9-10 December), with moderate rain potentially affecting Canterbury.
• After a mostly dry Monday (11 December), scattered showers will be possible on Tuesday, with more widespread showers possible on Wednesday.
• Generally dry weather is likely on Thursday, but another front may bring more rain to the West Coast on Friday (15 December).
• Weekly rainfall totals of 100-250 mm are possible in the West Coast, with 30-50 mm possible in interior Canterbury and Southland.
• However, lighter amounts of 25 mm or less are forecast in the upper South Island, coastal Canterbury, and Otago.
• Due to the expected rainfall in the next week, soil moisture decreases may occur in Nelson, Marlborough Sounds, coastal Canterbury, and Otago, with minor to moderate increases possible elsewhere.
• The current hotspots in Marlborough Sounds and Nelson may strengthen in the next week, while the hotspot in Banks Peninsula may not change substantially.  

Long-term outlook (through early January):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios both favour widespread drier or much drier than normal conditions across both islands through early January.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still favoured in large parts of both islands.
• Very dry soil conditions could begin to affect large swaths of both islands in the drier rainfall scenario.   

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A new study has comprehensively mapped the immediate after effects of the January 2022 eruption of Hunga Tonga – Hunga Ha’apai, highlighting the risks of similar events.

The study, published in Nature Communications, is part of the joint international project, the NIWA-Nippon Foundation Tonga Eruption Seabed Mapping Project (TESMaP), which includes 13 partners from Tonga, New Zealand, Australia, Germany, USA, and the UK. 

The eruption was the biggest atmospheric explosion recorded on Earth in more than 100 years, displacing almost 10km3 of seafloor, and generating a tsunami that sent shockwaves around the world.

Following the eruption, scientists from New Zealand’s National Institute of Water and Atmospheric Research (NIWA) set sail on RV Tangaroa for a month-long voyage to collect geological data, video footage, seabed imagery and water column samples. Using this information, they were able to show the far-reaching ocean impacts of such a large eruption, including the widespread loss of seafloor life.

NIWA biogeochemist and lead author of the study Dr Sarah Seabrook says the initial voyage has led to discoveries never before seen, reshaping our understanding of the impacts of volcanic eruptions on ocean ecosystems.

“Just one example is the role of underwater mountains (seamounts) providing a sheltering effect from the powerful seafloor density currents that smothered much of the seafloor around the volcano, wiping out seafloor life in the area, but left the seamounts relatively unscathed,” Dr Seabrook says. 

“Such refugia have been reported on land, where vegetation and people have been sheltered, but not in the ocean. But survival after the initial event is only the first hurdle. The eruption causes dramatic changes to nutrient and oxygen levels in the water which could have feedbacks that we are yet to understand.

“We do not know the timescale over which the seafloor communities in the Hunga Volcano may recover, but we think it may be aided by re-colonisation of the life which survived near these seamounts. The only way to see if it has survived, and to what extent, is to revisit the area.”

She says that most eruptions of submarine volcanoes go undetected or underreported with little data before or after eruptions.

Dr Seabrook says that there is still much to be learned about the 22 mapped volcanoes in the Kingdom of Tonga, along with hundreds more along the Tonga-Tofua-Kermadec Arc, and numerous others worldwide.“Future monitoring, of both the volcanic edifice itself and the surrounding seafloor and habitats, is necessary to robustly determine the resilience and recovery of both human and natural systems to major submarine eruptions. It will also help more broadly assess the risks posed by the many similar submerged volcanoes that exist worldwide.”

Dr Isobel Yeo is a volcanologist, and lead scientist of the UK part of this international programme, based at the National Oceanography Centre (NOC).

“This work has highlighted the potential of offshore volcanoes to produce immense eruptions that pose a serious threat to coastal communities and subsea infrastructure, and highlights the urgent need for more research on and monitoring of these volcanic systems, not just in Tonga, but globally,” she says. 

Dr James Hunt of the UK’s National Oceanography Centre says international partnerships were key to the success of the research. “This complex project required mobilisation of a vessel immediately after the eruption and brought together a truly multidisciplinary science team. This could only be achieved through international collaborations, underlining a need to work across borders to understand volcanic hazards.”

Source: NIWA – National Institute of Water and Atmospheric Research

A new study has comprehensively mapped the immediate after effects of the January 2022 eruption of Hunga Tonga – Hunga Ha’apai, highlighting the risks of similar events.

The study, published in Nature Communications, is part of the joint international project, the NIWA-Nippon Foundation Tonga Eruption Seabed Mapping Project (TESMaP), which includes 13 partners from Tonga, New Zealand, Australia, Germany, USA, and the UK. 

The eruption was the biggest atmospheric explosion recorded on Earth in more than 100 years, displacing almost 10km3 of seafloor, and generating a tsunami that sent shockwaves around the world.

Following the eruption, scientists from New Zealand’s National Institute of Water and Atmospheric Research (NIWA) set sail on RV Tangaroa for a month-long voyage to collect geological data, video footage, seabed imagery and water column samples. Using this information, they were able to show the far-reaching ocean impacts of such a large eruption, including the widespread loss of seafloor life.

NIWA biogeochemist and lead author of the study Dr Sarah Seabrook says the initial voyage has led to discoveries never before seen, reshaping our understanding of the impacts of volcanic eruptions on ocean ecosystems.

“Just one example is the role of underwater mountains (seamounts) providing a sheltering effect from the powerful seafloor density currents that smothered much of the seafloor around the volcano, wiping out seafloor life in the area, but left the seamounts relatively unscathed,” Dr Seabrook says. 

“Such refugia have been reported on land, where vegetation and people have been sheltered, but not in the ocean. But survival after the initial event is only the first hurdle. The eruption causes dramatic changes to nutrient and oxygen levels in the water which could have feedbacks that we are yet to understand.

“We do not know the timescale over which the seafloor communities in the Hunga Volcano may recover, but we think it may be aided by re-colonisation of the life which survived near these seamounts. The only way to see if it has survived, and to what extent, is to revisit the area.”

She says that most eruptions of submarine volcanoes go undetected or underreported with little data before or after eruptions.

Dr Seabrook says that there is still much to be learned about the 22 mapped volcanoes in the Kingdom of Tonga, along with hundreds more along the Tonga-Tofua-Kermadec Arc, and numerous others worldwide.“Future monitoring, of both the volcanic edifice itself and the surrounding seafloor and habitats, is necessary to robustly determine the resilience and recovery of both human and natural systems to major submarine eruptions. It will also help more broadly assess the risks posed by the many similar submerged volcanoes that exist worldwide.”

Dr Isobel Yeo is a volcanologist, and lead scientist of the UK part of this international programme, based at the National Oceanography Centre (NOC).

“This work has highlighted the potential of offshore volcanoes to produce immense eruptions that pose a serious threat to coastal communities and subsea infrastructure, and highlights the urgent need for more research on and monitoring of these volcanic systems, not just in Tonga, but globally,” she says. 

Dr James Hunt of the UK’s National Oceanography Centre says international partnerships were key to the success of the research. “This complex project required mobilisation of a vessel immediately after the eruption and brought together a truly multidisciplinary science team. This could only be achieved through international collaborations, underlining a need to work across borders to understand volcanic hazards.”

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Substantial rainfall of 60-100 mm was observed across Gisborne and northern Hawke’s Bay in the past week.
• However, much less rainfall occurred elsewhere across the North Island, where totals were generally less than 25 mm.   
• Particularly meagre rainfall was observed in Northland, Auckland, and northern Waikato.
• This resulted in small to moderate soil moisture decreases across a majority of the North Island, although little change was observed in Gisborne and Hawke’s Bay.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in Kapiti Coast, while the wettest soils for this time of the year are found in parts of Gisborne and Hawke’s Bay.
• No hotspots currently exist in the North Island.
• As of 27 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the North Island.

South Island:

• Rainfall amounts of 30-50 mm were observed in much of the West Coast and Fiordland, along with portions of northern and central Canterbury.
• Elsewhere in the South Island, rainfall amounts of 25 mm or less were generally observed.
• This resulted in at least minor soil moisture decreases across much of the South Island, although minor increases were observed in central Canterbury.    
• The driest soils across the South Island, when compared to normal for this time of the year, are found in Marlborough Sounds and coastal Southland, while the wettest soils for this time of the year are found in western Tasman.
• In the past week, the hotspot located in coastal Banks Peninsula and Selwyn District dissipated, while a new hotspot formed in Marlborough Sounds.

As of 27 November, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Nelson, Marlborough, North Canterbury, and Banks Peninsula.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 27 November, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Nelson, Marlborough, North Canterbury, and Banks Peninsula. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• Scattered showers will be possible on Friday and Saturday (1-2 December), but many parts of the North Island will remain dry.
• Moderate to heavy rain may overspread much of the island on Sunday and Sunday night.
• There is currently some uncertainty regarding the timing and amount of rainfall expected next week, but periods of at least moderate rain are possible from Tuesday (5 December).
• Weekly rainfall totals of 25-50 mm are forecast across a majority of the North Island, but localised higher amounts may occur.
• Due to the expected rainfall in the next week, a majority of the North Island is likely to see little change to soil moisture levels, or small increases.
• No hotspots are expected to form in the North Island in the next week.

South Island:

• Other than isolated showers, mostly dry weather is expected through Saturday morning (2 December), followed by rain for many regions through Sunday. Heavy rain will affect the West Coast during this time.
• After showers on Monday (4 December), mostly dry weather is expected through Wednesday morning.
• During the middle of next week, another front could bring lighter rain to the West Coast.
• Weekly rainfall totals of 100-200 mm are generally expected in the West Coast, with 30-50 mm possible in interior areas.
• However, lighter amounts of 25 mm or less are forecast along the east coast, Otago, and Southland.
• Due to the expected rainfall in the next week, soil moisture decreases may occur in the lower South Island, with minor increases possible in the West Coast.
• The current hotspot in Marlborough Sounds may not change significantly in the next week, while coastal Southland could approach hotspot criteria.

Long-term outlook (through late December):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios both favour drier or much drier than normal conditions in the upper and eastern North Island and eastern South Island.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still favoured in the lower South Island.
• Near normal to above normal rainfall is favoured for the North Island in the wetter scenario.

Very dry or meteorological drought conditions are unlikely to develop in the next 35 days, but cannot be ruled out under the driest-case scenario for parts of the South Island.  

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Substantial rainfall of 40-80 mm was widespread across the central and eastern North Island in the past week, along with Taranaki. Isolated amounts above 100 mm were also observed in these areas.
• However, much less rainfall occurred in much of Northland, Auckland, Manawatū-Whanganui, and Wellington, where generally less than 20 mm fell.   
• This resulted in moderate soil moisture increases across large portions of the North Island.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in Kapiti Coast, while the wettest soils for this time of the year are found along the east coast and in western Bay of Plenty.
• No hotspots currently exist in the North Island.
• As of 20 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the North Island.

South Island:

• Rainfall amounts of 75-100 mm were observed in Fiordland in the past week, with 25-40 mm in the rest of the West Coast.
• Amounts of 15-30 mm occurred from southern Canterbury to Otago, with only 5 mm or less in much of Marlborough, northern and central Canterbury, and lower Southland.
• This resulted in moderate soil moisture decreases across a majority of the South Island.   
• The driest soils across the South Island, when compared to normal for this time of the year, are found in much of coastal Southland, while the wettest soils for this time of the year are found in northern Canterbury and Tasman.
• In the past week a new hotspot formed in parts of coastal Banks Peninsula and Selwyn District.
• As of 20 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the South Island.

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Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 20 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the country. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• Rain will move across the North Island on Friday (24 November), with areas of heavy rain continuing in Gisborne and parts of Hawke’s Bay on Saturday and Sunday (25-26 November).
• Early next week will be mostly dry, but scattered showers and thunderstorms may arrive on Wednesday (29 November).
• A more significant rain event may impact the North Island late next week.
• Weekly rainfall totals greater than 100 mm may occur in Gisborne and parts of Hawke’s Bay, with 25-50 mm possible in the rest of the east coast and the Central Plateau.
• However, much less rainfall is forecast from Northland to northern Waikato, where less than 15 mm is expected.
• Due to the expected rainfall in the next week, parts of the east coast and central North Island will likely see at least small soil moisture increases, but small decreases are favoured in the upper North Island.
• No hotspots are expected to form in the North Island in the next week.

South Island:

• Scattered showers will affect much of the east coast on Friday (24 November), with dry conditions along the West Coast.
• Dry weather is expected during the weekend, followed by isolated showers on Monday (27 November).
• Showers or rain will again be possible on Tuesday, followed by another day or two of dry weather.
• Weekly rainfall totals of 30-70 mm are generally expected in the West Coast, with 20-40 mm possible in northern Canterbury, Otago, and Southland.
• Elsewhere, less than 20 mm of total rainfall are likely.
• Due to the expected rainfall in the next week, soil moisture levels may decrease slightly in parts of the upper and eastern South Island.
• The current hotspot along the central Canterbury coast may strengthen slightly in the next week, while Marlborough Sounds may begin to approach hotspot criteria.

Long-term outlook (through late December):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios both favour drier or much drier than normal conditions in the upper North Island and lower South Island.
• The wetness in the eastern North Island is mostly tied to the expected heavy rainfall in the next few days.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still favoured in parts of the lower South Island.
• Unusual dryness and drought are not expected in the next 35 days.  

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook

Background:  

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island: 

• Meagre rainfall was widespread across the North Island in the past week, with nearly all locations receiving less than 5 mm. 
• This resulted in moderate soil moisture decreases across the entire North Island.  
• The driest soils across the North Island, when compared to normal for this time of the year, are found in western Waikato and Kapiti Coast, while the wettest soils for this time of the year are found in southern Gisborne, northern Hawke’s Bay, and parts of the Far North. 
• No hotspots currently exist in the North Island.
• As of 14 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the North Island.

South Island:

• Rainfall amounts of 10 mm or less were widespread across the upper and eastern South Island in the past week.
• While the upper West Coast received 20-40 mm, the central West Coast received 40-80 mm.
• In addition, heavy rainfall of 150 mm or more was observed in much of Fiordland.
• This resulted in moderate soil moisture decreases across the upper and eastern South Island, with small to moderate increases observed in parts of the West Coast and Fiordland.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in Marlborough Sounds, while the wettest soils for this time of the year are found in northern Canterbury.
• No hotspots currently exist in the South Island.
• As of 14 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the South Island.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks. 

As of 14 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the country. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

New Zealand Drought Index (NZDI) – 14 Nov 2023 [NIWA].

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook

Background: 

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent.  

Soil moisture deficit: the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold. 

Soil moisture anomaly: the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm. 

Source: NIWA – National Institute of Water and Atmospheric Research

NIWA has developed a Photarium using the latest 3D printing technology to more safely identify and measure fish species that live in our waterways.

According to Statistics NZ, 76 percent of the 51 indigenous freshwater fish species in New Zealand are threatened with extinction or at risk of becoming threatened, so education, data and research are critical to understanding how better to identify, protect and sustainably manage these species.

Photariums are indispensable tools used by photographers, researchers, and educators around the world to safely observe live fish in the field, but they are currently only made in the United States and do not ship to New Zealand.

NIWA Freshwater Ecologist Peter Williams took matters into his own hands. He developed his own Photarium and is producing it easily and affordably using a new industrial grade 3D printer NIWA recently acquired.

“An older 3D printer would have only produced a prototype quality unit and we would have needed a costly specialist manufacturer to make the finished product,” he says.

“NIWA’s new 3D printer is more advanced and allows us to produce a quality product at low cost which means its accessible to those who need it here in Aotearoa.”.

A Photarium is a small plastic rectangular box, with a clear side and built-in ruler. It allows small fish to be studied without being handled or taken out of the water. It also has a hinged flap to block out light and give the fish privacy to reduce stress during transportation.

Williams designed the NIWA Photarium based on his 14 years of field experience and has been able to adapt and modify it for sampling small fish species in New Zealand’s waterways.

“Many of our native species are climbing fish and the top part of the lid can be closed to stop the fish from jumping out. A mesh that’s printed into this hatch cover allows us to top up the water level for better photography,” he says.

“The beauty of the 3D printer is it allows NIWA to produce Photariums on demand and to keep improving our design based on what we discover while using them in the field.”

The NIWA Photarium improves the accuracy of fish identification. It allows collection and release with minimum handling, and without the use of anaesthetics, which if not done properly can lead to mortality in the fish. It enables small and delicate life stages of fish to be accurately observed and photographed without harming the fish.

Given its success in improving the accuracy of fish identification and photography, NIWA has already had over 70 orders for its Photarium from regional councils, rūnanga, DOC, and education groups across the country.

Williams is also showcasing the benefits of the newly available Photariums as part of NIWA’s electric fishing operator course, which he runs nationwide.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• In the past week, substantial rainfall amounts of 40-100 mm were observed in parts of Bay of Plenty, Gisborne, northern Hawke’s Bay, the Central Plateau, and Taranaki.
• Across the rest of the North Island, rainfall amounts in the past week were generally 25 mm or less.
• This resulted in large soil moisture increases across much of the eastern and central North Island where the heaviest rainfall occurred. Elsewhere, soil moisture changes were generally minimal.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in northern Waikato, while the wettest soils for this time of the year are found in southern Gisborne and northern Hawke’s Bay.
• No hotspots currently exist in the North Island.
• As of 7 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the North Island.

South Island:

• Rainfall of 30-60 mm occurred across much of the upper South Island in the past week, along with pockets of central Canterbury and Otago.
• Most other locations received 15-25 mm.
• However, western Southland and much of Fiordland received only 5 mm or less in the past week.
• This resulted in moderate soil moisture increases across much of the upper and eastern South Island, with small decreases observed in parts of Southland and Fiordland.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in south western Southland, while the wettest soils for this time of the year are found in northern Canterbury.
• No hotspots currently exist in the South Island.
• As of 7 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the South Island.

 Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 7 November, the New Zealand Drought Index (NZDI) map below shows that no unusually dry conditions are currently found across the country. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• A large area of high pressure over the North Island will result in generally dry weather through Monday (13 November). During this time only isolated, light showers may occur.
• On Tuesday and Wednesday (14-15 November), a more organised front may bring moderate rain to the western North Island.
• Towards the end of next week, another front could deliver more moderate to heavy rainfall.
• Weekly rainfall totals of 30-60 mm will be favoured across the western half of the North Island, although the east coast may see much less rainfall, generally less than 20 mm.
• Due to the expected rainfall in the next week, soil moisture levels may increase in the western North Island, while minor decreases may occur in the east.
• No hotspots are expected to form in the North Island in the next week. 

South Island:

• Generally dry weather is expected through this weekend, although Fiordland and the lower West Coast will see rain developing on Sunday (12 November).
• Heavy rain will affect the West Coast on Monday (13 November), with a period of moderate rain on Tuesday night.
• By late Thursday and Friday, low pressure in the Tasman Sea could deliver another round of heavy rain to the western South Island, and a potential for some moderate rain in the east.
• Weekly rainfall totals could exceed 150 mm in the central and lower West Coast, with a bit less farther north. Totals of 20-50 mm will be possible from southern Canterbury to Southland.
• However, eastern Marlborough and northern Canterbury may receive less than 20 mm.
• Due to the expected rainfall in the next week, soil moisture levels could increase moderately in the western and lower South Island, but minor decreases may occur in eastern Marlborough and northern Canterbury.
• No hotspots are expected to form in the South Island in the next week.

Long-term outlook (through mid-December):

• High pressure and less rainfall than normal will become strongly favoured by late November.
• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios both favour drier or much drier than normal conditions across much of the country, especially in the upper North Island and eastern South Island.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still favoured in parts of these same areas.
• In the drier rainfall scenario, there is a signal for dry conditions to emerge in pockets of both islands.  

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.