![Page 1: The Impact of the Reduced Radiosonde Observation in Russia on GRAPES Global Model Weihong Tian, Ruichun Wang, Shiwei Tao, Xiaomin Wan Numerical Prediction](https://reader034.vdocuments.mx/reader034/viewer/2022051517/5697c02b1a28abf838cd85ab/html5/thumbnails/1.jpg)
The Impact of the Reduced Radiosonde Observation in Russia on GRAPES Global Model
Weihong Tian, Ruichun Wang, Shiwei Tao, Xiaomin Wan
Numerical Prediction Center of CMA
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Contents
• Background• Russia Radiosonde quality assessment• Impact study • Summary
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Background• Russia reduced & adjusted radiosonde observation
from January 2015.• The impact caused by reduced data on GRAPES
global model need to assess.
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RAOB data coverage in 1 Jan 2015
RAOB data coverage in 1 Jan 2014
00UTC. 12UTC.
00UTC. 12UTC.
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The location of reduced radiosonde coverage
Blue dots for 12UTC(51) Red dots for 00UTC(28).
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RS92/III Reduced stationHeight
Temperature
O-A (ERA) statistic: Reduced observations at 00UTC compared with Vaisala RS92/Digicora III (Finland)
RS92/III Reduced station
negative bias
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Temperature observation bias (10hpa)
Vaisala RS92/Digicora III (Finland) AVK-MRZ (Russian Federation)
Summer Winter
Kelvin
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RS92/III
U-Wind
Reduced station
RS92/III Reduced station
O-A (ERA) statistic: Reduced observations at 00UTC compared with Vaisala RS92/Digicora III (Finland)
V-Wind
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Impact Study I
• Experiments: Use RAOB Pressure observation– GRAPES 3DVar global data assimilation system– Resolution :0.5*0.5 *62– Observations:
• GTS conventional data, AMV, NOAA-15 /16/18/19 AMSUA
• METOP-A AMSUA– No temperature bias correction for all RAOB– Experimental Period : 1-31 January 2014– Test 1 : use all the data (control)– Test 2 : reduced radiosonde observation
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GRAPES Height analysis bias compare with FNL at 00UTC
Reduce RAOB at 00UTC decrease the height analysis bias
All data
Reduce RAOB
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GRAPES Height analysis bias compare with FNL at 12UTC
Reduce RAOB at 12UTC has neutral impact on height
All data
Reduce RAOB
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00UTCu-wind analysis bias compare with FNL (700hpa)
All data
Reduce RAOB
Reduce RAOB at 00UTC increase the wind analysis bias
![Page 13: The Impact of the Reduced Radiosonde Observation in Russia on GRAPES Global Model Weihong Tian, Ruichun Wang, Shiwei Tao, Xiaomin Wan Numerical Prediction](https://reader034.vdocuments.mx/reader034/viewer/2022051517/5697c02b1a28abf838cd85ab/html5/thumbnails/13.jpg)
12UTCu-wind analysis bias compare with FNL (700hpa)
All data
Reduce RAOB
Reduce RAOB at 12UTC has neutral impact on wind
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GRAPES Height analysis Bias & RMSE (Unit:m)
East AsiaRussia
( 40-90N, 0-180E)
Russia
East Asia
BiasBias
RMSE RMSE
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GRAPES U-wind analysis RMSE (Unit:m/s)
Russia East Asia
( 40-90N,0-180E)
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00UTC
Anomaly correlation coefficient 00/12UTC
East Asia
12UTC
East Asia
NH
NH
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Impact Study II
• Experiments: Use RAOB Temperature observation– GRAPES 3DVar global data assimilation system– Resolution :0.5*0.5 *60 (new model version)– Observations:
• No AMDAR Temp obs (Temp bias), use wind observation• GTS conventional data, AMV, NOAA-15 /16/18/19 AMSUA• METOP-A AMSUA, GPS/RO Refractivity
– No temperature bias correction for all RAOB– Experimental Period : 1-31 May 2013– Test 1 : use all the data (control)– Test 2 : reduced radiosonde observation
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00UTCHeight analysis bias compare with ERA (700hpa)
Reduce RAOB at 00UTC has neutral impact
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00UTCu-wind analysis bias compare with ERA (250hpa)
Reduce RAOB at 00UTC increase the wind analysis bias
![Page 20: The Impact of the Reduced Radiosonde Observation in Russia on GRAPES Global Model Weihong Tian, Ruichun Wang, Shiwei Tao, Xiaomin Wan Numerical Prediction](https://reader034.vdocuments.mx/reader034/viewer/2022051517/5697c02b1a28abf838cd85ab/html5/thumbnails/20.jpg)
GRAPES Height analysis Bias & RMSE (Unit:m)
East AsiaRussia
( 40-90N, 0-180E)
Russia
East Asia
BiasBias
RMSE RMSE
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Wind analysis error
Russia
( 40-90N, 0-180E)
East Asia
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Summary• RAOBs in Russia have large negative temperature
bias. bias correction is needed. • The reduced RAOB in Russia has clear negative
impact on wind analysis• but with neutral impact on geopotential height
analysis.
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Thank you for attention!