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Monthly Discussion on Seasonal Climate Outlooks (No. 73)
(25 March 2020)
Tokyo Climate Center (TCC)Japan Meteorological Agency (JMA)
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Outline
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Notes:• The present monthly discussion is intended to assist National Meteorological and
Hydrological Services (NMHSs) in WMO RA II (Asia) in interpreting WMC Tokyo’sseasonal prediction products. It does not constitute an official forecast for any nation.Seasonal outlooks for individual countries should be obtained from the relevant NMHS.
• Seasonal predictions are based on a JMA’s Seasonal Ensemble Prediction System (EPS),which is based on the coupled atmosphere-ocean general circulation model (CGCM).
• JMA provides three-month prediction products around the 20th of every month withwarm-season (Jun. – Aug.) prediction products in February, March and April, and withcold-season (Dec. – Feb.) prediction products in September and October.
1. Summary and Discussion <Slides 3 – 4>
2. Latest State of the Climate System (Feb. 2020) <Slides 5 – 15>
3. Three-month Predictions (Apr. 2020 – Jun. 2020) <Slides 16 – 22>
4. Warm Season Predictions (Jun. 2020 – Aug. 2020) <Slides 23 – 29>Explanatory Notes <Slides 30 – 34>
1. Summary and DiscussionENSO
• ENSO-neutral conditions persisted.• ENSO-neutral conditions are likely (60%) to continue until boreal summer.
Prediction for April-May-June 2020 (AMJ 2020)• In the upper troposphere, large-scale divergence anomalies are predicted over the western
tropical Indian Ocean, and large-scale convergence anomalies are predicted over the centraltropical South Pacific and from the northeastern tropical Indian Ocean to the Philippines.
• A high probability of above-normal precipitation is predicted in and around the southwesterntropical Indian Ocean. A high probability of below-normal precipitation is predicted from thenortheastern tropical Indian Ocean to the Philippines.
• A high probability of above-normal temperatures is predicted over the southern part of theMiddle East, Southeast Asia, and part of East Asia.
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1. Summary and Discussion (cont.)Prediction for June-July-August 2020 (JJA 2020)• In the upper troposphere, large-scale divergence anomalies are predicted over the western
tropical Indian Ocean, and large-scale convergence anomalies are predicted over the westerntropical Pacific.
• A high probability of above-normal precipitation is predicted over the southern part ofSoutheast Asia.
• A high probability of above-normal temperatures is predicted over the Middle East,Southeast Asia, and part of East Asia.
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2. Latest State of the Climate System February 2020
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6<Monthly Report on Global Extreme Climate Events> https://ds.data.jma.go.jp/tcc/tcc/products/climate/monthly/index.html
<February 2020> Extreme Climate Events
<February 2020> Temperature
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Normalized anomaly of monthly mean temperature
• Monthly mean temperatures were extremely high from the northwestern part of Eastern Siberia to thenorthern part of Western Siberia, from eastern Japan to central China, from southwestern India to SriLanka, from the central part of Western Siberia to the northwestern part of Central Asia, from centralEurope to the northwestern part of Northern Africa, in the western part of Western Africa, in and aroundnorthern Madagascar, in the northeastern USA, from the northwestern part of Central America to thenorthern part of South America, and from northeastern Australia to the southern part of Southeast Asia.
<World Climate Chart (Monthly)> https://ds.data.jma.go.jp/tcc/tcc/products/climate/climfig/?tm=monthly
<February 2020> Precipitation
Monthly precipitation ratio
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• Monthly precipitation amounts were extremely high from northeastern China to the central part ofCentral Asia, from northwestern Russia to northwestern Europe, in the southeastern USA, and insoutheastern Brazil.
• Monthly precipitation amounts were extremely low from southern Europe to the northwestern part ofNorthern Africa, in the western USA, and from northern Argentina to Uruguay.
<World Climate Chart (Monthly)> https://ds.data.jma.go.jp/tcc/tcc/products/climate/climfig/?tm=monthly
<February 2020> Sea Surface Temperature (SST)
Monthly mean SST anomaly (˚C)
• In the equatorial Pacific, remarkably positive SST anomalies were observed in the western part.
• In the North Pacific, remarkably positive SST anomalies were observed from south of Japan to far east ofJapan, from the Gulf of Alaska to around the Hawaiian Islands, and in the southwestern coast of Mexico.
• In the Indian Ocean, remarkably positive SST anomalies were observed in almost the entire tropical region.
9<Monthly mean SST anomalies (Global)> https://ds.data.jma.go.jp/tcc/tcc/products/elnino/ocean/sst-ano-global_tcc.html
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<February 2020> ENSO Monitoring Indices
Monthly values (thin lines) and five-month running means (thick lines). The shading indicates El Niño (red) and La Niña (blue) events.
NINO.3
NINO.WEST
IOBW
• ENSO-neutral conditions persisted.
• The NINO.3 SST was near normal witha deviation of 0.0ºC.
• The Southern Oscillation Index (SOI)value was 0.0.
• The area-averaged SST in the tropicalwestern Pacific (NINO.WEST) regionwas below normal.
• The area-averaged SST in the tropicalIndian Ocean (IOBW) region was abovenormal.
< El Niño Monitoring and Outlook> https://ds.data.jma.go.jp/tcc/tcc/products/elnino/elmonout.html
SOI
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<February 2020> Convective activity in the Tropics
<Monthly Mean Figures> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/figures/db_hist_mon_tcc.html<Animation Maps (Global Area)> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/anim_tp.html
Monthly mean Velocity potential, Divergent wind vector, andVelocity potential anomaliesat 200-hPaContour: velocity potential (106m2/s)Vector: divergent wind vector (m/s)Shading: velocity potential anomalies (106m2/s)“D” and “C” indicate the centers of large-scale divergence and convergence anomalies, respectively.
Monthly mean OLR anomaliesShading: OLR anomalies (W/m2)
• Convective activity was enhanced over the western equatorial Indian Ocean, around the date line in theequatorial Pacific, and over the latitude band of 10ºN in the central tropical North Pacific, andsuppressed over the Maritime Continent and the northern part of South America.
MJO diagram
<February 2020> Equatorial Intraseasonal Oscillation• The active phase of equatorial intraseasonal oscillation propagated eastward from the Maritime
Continent via the Pacific to Africa.
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Time-longitude cross section of seven-day running mean velocity potential anomalies at 200-hPa (5˚S – 5˚N)
<MJO> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/mjo/moni_mjo.html
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<February 2020> Upper-level Circulation
<Monthly Mean Figures> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/figures/db_hist_mon_tcc.html<Animation Maps (Global Area)> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/anim_tp.html
Monthly mean Velocity potential, Divergent wind vector andVelocity potential anomaliesat 200-hPaContour: velocity potential (106m2/s)Vector: divergent wind vector (m/s)Shading: velocity potential anomalies (106m2/s)“D” and “C” indicate the centers of large-scale divergence and convergence anomalies, respectively.
Monthly mean Stream function andits anomalies at 200-hPaContour: stream function (106m2/s)Shading: stream function anomalies (106m2/s )“H” and “L” indicate the centers of anti-cyclonic and cyclonic circulations, respectively.
• In the upper troposphere, cyclonic circulation anomalies were seen over Northern Africa, southern China,the central and eastern tropical North Pacific, and the western tropical North Atlantic, and anti-cycloniccirculation anomalies were seen over the Arabian Sea and the central tropical southern Indian Ocean.
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<February 2020> Low-level Circulation
<Monthly Mean Figures> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/figures/db_hist_mon_tcc.html<Animation Maps (Global Area)> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/anim_tp.html
Monthly mean Sea level pressure anomalies and Surface wind vector anomalies Contour&shading: sea level pressure anomalies (hPa)Vector: surface wind vector anomalies (m/s)“H” and “L” indicate the centers of anti-cyclonic and cyclonic anomalies, respectively.
Monthly mean Stream function andits anomalies at 850-hPaContour: stream function (106m2/s)Shading: stream function anomalies (106m2/s)“H” and “L” indicate the centers of anti-cyclonic and cyclonic circulations, respectively.
• In the lower troposphere, cyclonic circulation anomalies straddling the equator were seen over the west of thedate line in the tropical Pacific, and anti-cyclonic circulation anomalies straddling the equator were seenaround Southeast Asia.
• In the sea level pressure field, in the equatorial area, positive anomalies were seen except from the date line tothe central Pacific.
<February 2020> Northern Hemisphere Circulation• In the 500-hPa height field, positive anomalies were seen from Central Siberia to Japan, over the mid-latitudes of the eastern
North Pacific, and from the latitude band of 40ºN in the North Atlantic to southern Europe, and negative anomalies were seenover a wide area of the northern polar region. Wave trains were seen from the mid-latitudes of the eastern North Pacific toCaribbean countries, and from Greenland via Northern Africa to southern East Asia.
• Temperatures at 850-hPa were above normal from the latitude band of 40ºN in the North Atlantic via Central Siberia to Japan,and over the seas west of the USA, and below normal over the Chukchi Sea, and the seas south and northeast of Greenland.
• In the sea level pressure field, positive anomalies were seen over northern South Asia, near Japan, the seas west of the USA, andNorthern Africa, and negative anomalies were seen over a wide area of the northern polar region. The Aleutian Low wasstronger than normal around the Aleutian Islands.
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Monthly mean geopotential heightand its anomalies at 500-hPa Contour: geopotential height (m)Shading: geopotential height anomalies (m)
<Monthly Mean Figures> https://ds.data.jma.go.jp/tcc/tcc/products/clisys/figures/db_hist_mon_tcc.html
Monthly mean temperatureand its anomalies at 850-hPa Contour: temperature (˚C)Shading: temperature anomalies (˚C)
Monthly mean sea level pressureand its anomaliesContour: sea level pressure (hPa)Shading: sea level pressure anomalies (hPa)
3. Three-month PredictionsApril – May – June 2020 (AMJ 2020)(Initial date for the Seasonal EPS: 7 March 2020)
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<AMJ 2020> Sea Surface Temperature (SST)
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Three month mean Sea surface temperature (SST) Contour: SST (˚C); Shading: SST anomalies.
Outlook of the SST deviation
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.htmlhttps://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/shisu/shisu.html
(c) NINO.3(b) NINO.WEST(a) IOBW
(b)(a)
(c)
ENSO forecast probabilities
• ENSO-neutral conditions are likely (60%) to continue until boreal summer.• The NINO.WEST SST is likely to be below or near normal during boreal spring and near or above normal
in boreal summer.• The IOBW SST is likely to be above normal during boreal spring and above or near normal in boreal
summer.
(See “Explanatory Notes (2)”for the definition of the SST indices.)
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<AMJ 2020 > Global Circulation• In the 200-hPa velocity potential field, negative (large-scale divergence) anomalies are predicted over
the western tropical Indian Ocean, and positive (large-scale convergence) anomalies are predicted overthe central tropical South Pacific and from the northeastern tropical Indian Ocean to the Philippines.
• In the 200-hPa stream function field, cyclonic circulation anomalies are predicted in and around thesouthern part of East Asia and over the latitude band of 30ºN in the western and central North Pacific.
Three month mean200-hPa velocity potentialContour: 200-hPa velocity potential (106 m2/s)Shading: 200-hPa velocity potential anomalies (106 m2/s)
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.html
Three month mean200-hPa stream functionContour: 200-hPa stream function (106 m2/s)Shading: 200-hPa stream function anomalies (106 m2/s)
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<AMJ 2020> Asian Circulation
Verification based on hindcast https://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.html
Three month mean(a) 850-hPa stream function anomaliesand wind vector anomaliesContour&Shading: 850-hPa stream function anomalies (106 m2/s) Vector: wind vector anomalies (m/s)
(b) sea level pressure and its anomaliesContour: sea level pressure (hPa)Shading: sea level pressure anomalies (hPa)
(c) precipitation and its anomaliesCoutour: precipitation (mm/day)Shading: precipitation anomalies (mm/day)
(b)
(a)
(c)
[m/s]
• In the 850-hPa stream function field, anti-cycloniccirculation anomalies straddling the equator are predictedfrom the tropical Indian Ocean to the Maritime Continent.
• In the sea level pressure field, positive anomalies arepredicted over large area from tropical Indian Ocean to thetropical western Pacific, and negative anomalies arepredicted over the southwestern tropical Indian Ocean.
• Above-normal precipitation is predicted from the southerntropical Indian Ocean to the western tropical North Pacific.Below-normal precipitation is predicted from thenortheastern tropical Indian Ocean to the Philippines.
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<AMJ 2020> Northern Hemisphere circulation• In the 500-hPa height field, positive anomalies are predicted over Europe and from Central Siberia to the
northern part of the North Pacific.• In the 850-hPa temperature field, positive anomalies are dominantly predicted over the Northern
Hemisphere, especially from Central Siberia to the northern part of the North Pacific.• In the sea level pressure field, positive anomalies are predicted west of Europe, over the southern part of
Central and Eastern Siberia, and south of the Aleutian Islands, and negative anomalies are predicted overthe northern polar region.
Verification based on hindcast https://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.html
Three month mean geopotential heightand its anomalies at 500-hPa Contour: geopotential height (m)Shading: geopotential height anomalies (m)
Three month mean temperatureand its anomalies at 850-hPa Contour: temperature (˚C)Shading: temperature anomalies (˚C)
Three month mean sea level pressure (SLP)and its anomaliesContour: sea level pressure (hPa)Shading: sea level pressure anomalies (hPa)
<AMJ 2020> Probability Forecasts (precipitation)
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• A high probability of above-normal precipitation is predicted in and around the southwestern tropicalIndian Ocean.
• A high probability of below-normal precipitation is predicted from the northeastern tropical Indian Oceanto the Philippines.
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/3-mon/hind/html/skill_reg_3-mon.htmlhttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/3-mon/hind/html/skill_2d_3-mon.html
<AMJ 2020> Probability Forecasts (temperature)
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• A high probability of above-normal temperatures is predicted over the southern part of the Middle East,Southeast Asia, and part of East Asia.
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/3-mon/hind/html/skill_reg_3-mon.htmlhttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/3-mon/hind/html/skill_2d_3-mon.html
4. Warm Season PredictionsJune – July – August 2020 (JJA 2020)(Initial date for the Seasonal EPS: 7 March 2020)
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<JJA 2020> Sea Surface Temperature (SST)
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Three month mean Sea surface temperature (SST) Contour: SST (˚C); Shading: SST anomalies.
Outlook of the SST deviation
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.htmlhttps://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/shisu/shisu.html
(c) NINO.3(b) NINO.WEST(a) IOBW
(b)(a)
(c)
ENSO forecast probabilities
• ENSO-neutral conditions are likely (60%) to continue until boreal summer.• The NINO.WEST SST is likely to be below or near normal during boreal spring and near or above normal
in boreal summer.• The IOBW SST is likely to be above normal during boreal spring and above or near normal in boreal
summer.
(See “Explanatory Notes (2)”for the definition of the SST indices.)
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<JJA 2020 > Global Circulation• In the 200-hPa velocity potential field, negative (large-scale divergence) anomalies are predicted over
the western tropical Indian Ocean, and positive (large-scale convergence) anomalies are predicted overthe western tropical Pacific.
• In the 200-hPa stream function field, cyclonic circulation anomalies are predicted over South Asia andeast of the Philippines.
Three month mean200-hPa velocity potentialContour: 200-hPa velocity potential (106 m2/s)Shading: 200-hPa velocity potential anomalies (106 m2/s)
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.html
Three month mean200-hPa stream functionContour: 200-hPa stream function (106 m2/s)Shading: 200-hPa stream function anomalies (106 m2/s)
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<JJA 2020> Asian Circulation
Verification based on hindcast https://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.html
Three month mean(a) 850-hPa stream function anomaliesand wind vector anomaliesContour&Shading: 850-hPa stream function anomalies (106 m2/s) Vector: wind vector anomalies (m/s)
(b) sea level pressure and its anomaliesContour: sea level pressure (hPa)Shading: sea level pressure anomalies (hPa)
(c) precipitation and its anomaliesCoutour: precipitation (mm/day)Shading: precipitation anomalies (mm/day)
(b)
(a)
(c)
[m/s]
• In the 850-hPa stream function field, anti-cycloniccirculation anomalies are predicted over the northern part ofthe Philippine Sea.
• In the sea level pressure field, positive anomalies arepredicted in and around the Philippine Sea, and negativeanomalies are predicted over the western tropical IndianOcean.
• Above-normal precipitation is predicted in and around thesouthern part of South Asia and the southern part ofSoutheast Asia.
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<JJA 2020> Northern Hemisphere circulation• In the 500-hPa height field, positive anomalies are dominantly predicted over the Northern Hemisphere,
especially from the southern part of Eastern Siberia to Alaska, in and around the southwestern USA, and inand around the Mediterranean Sea.
• In the 850-hPa temperature field, positive anomalies are also dominantly predicted over the NorthernHemisphere, especially over the northeastern part of East Asia, from the Sea of Okhotsk to the Bering Sea,in and around the southwestern USA, and in and around the Mediterranean Sea.
• In the sea level pressure field, negative anomalies are predicted over the latitude band of 40ºN from thenortheastern part of East Asia to the south of the Gulf of Alaska.
Verification based on hindcast https://ds.data.jma.go.jp/tcc/tcc/products/model/hindcast/CPS2/index.html
Three month mean geopotential heightand its anomalies at 500-hPa Contour: geopotential height (m)Shading: geopotential height anomalies (m)
Three month mean temperatureand its anomalies at 850-hPa Contour: temperature (˚C)Shading: temperature anomalies (˚C)
Three month mean sea level pressure (SLP)and its anomaliesContour: sea level pressure (hPa)Shading: sea level pressure anomalies (hPa)
<JJA 2020> Probability Forecasts (precipitation)
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• A high probability of above-normal precipitation is predicted over the southern part of Southeast Asia.
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/warm_cold_season/hind/html/skill_reg_warm_cold_season.htmlhttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/warm_cold_season/hind/html/skill_2d_warm_cold_season.html
<JJA 2020> Probability Forecasts (temperature)
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• A high probability of above-normal temperatures is predicted over the Middle East, Southeast Asia, andpart of East Asia.
Verification based on hindcasthttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/warm_cold_season/hind/html/skill_reg_warm_cold_season.htmlhttps://ds.data.jma.go.jp/tcc/tcc/products/model/probfcst/warm_cold_season/hind/html/skill_2d_warm_cold_season.html
Explanatory Notes (1)Latest state of the climate system• Extreme climate events and surface climate conditions are based on CLIMAT messages.For details, see https://ds.data.jma.go.jp/tcc/tcc/products/climate/index.html
• SST products are based on COBE-SST data.For details, see https://ds.data.jma.go.jp/tcc/tcc/products/elnino/index.html
• Atmospheric circulation products are based on JRA-55 data:https://jra.kishou.go.jp/JRA-55/index_en.htmlFor details, see https://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
• The base period for the normal is 1981 – 2010.
Three-month predictions and warm/cold season predictions• Products are generated using JMA’s seasonal EPS which is based on the CGCM.For details, see https://ds.data.jma.go.jp/tcc/tcc/products/model/index.html
• Unless otherwise noted, atmospheric circulation prediction products are based on theensemble mean, and anomalies are deviations from the 1981 – 2010 average for hindcasts.
30Contact: [email protected]
Explanatory Notes (2)SST monitoring indices (NINO.3, NINO.WEST and IOBW)• The SST baseline for NINO.3 region (5˚S – 5˚N, 150˚W – 90˚W) is defined as a monthlyaverage over a sliding 30-year period (e.g., 1990 – 2019 for 2020). The thresholds ofabove the baseline, near the baseline, and below the baseline categories are +0.5 and -0.5.
• The SST baselines for the NINO.WEST region (Eq. – 15˚N, 130˚E – 150˚E) and theIOBW region (20˚S – 20˚N, 40˚E – 100˚E) are defined as linear extrapolations with respectto a sliding 30-year period in order to remove the effects of significant long-term warmingtrends observed in these regions. The thresholds of above the baseline, near the baseline,and below the baseline categories are +0.15 and -0.15.
Contact: [email protected]
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Names of world regions
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WMO Regional Association regions
Reference: WMO General Regulations
https://ds.data.jma.go.jp/tcc/tcc/index.html
TCC website
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