Evaluation of seven different atmospheric reanalysis products in the - PowerPoint PPT Presentation

Evaluation of seven different atmospheric reanalysis products in the Arctic R. Lindsay and M. Wensnahan Polar Science Center, Applied Physics Laboratory University of Washington, Seattle WA Modeling, Analysis, Predictions, and Projections (MAPP) Seminar September 25, 2012

Reanalysis Models � NCEP-R1 � NCEP-R2 � CFSR � 20CR � MERRA � ERA-Int � JRA-25 � 1948–p � 1979–p � 1979–p � 1871-2008 � 1979–p � 1979–p � 1979-p � Time interval � T62 � T62 � T382 � T62 � 0.5º x 0.66º � T255 � T106 � Spatial (209 km) � (209 km) � (38 km) � (209 km) � (65 km) � (79 km) � (125 km) � Resolution � 28 to � 28 to � 63 to � 28 to � 72 to � 60 to � 40 to � Vertical levels � 3 hPa � 3 hPa � 0.26 hPa � 0.2 hPa � 0.1 hPa � 0.1 hPa � 0.4 hPa � Data Ensemble 3D Var � 3D Var � 3D Var � IAU � 4D-Var � 3D-Var � assimilation Kalman Filter � method � Sea Ice and Prescribed � Prescribed � Interactive � Prescribed � Prescribed � Prescribed � Prescribed � SST �

2-m Air Temperatures

T2m, Winter Median T2M, Winter, 1980-2009 NCEP_R1 T2M Anomaly NCEP_R2 T2M Anomaly 20CR T2M Anomaly Median, C/yr Anomaly, C Anomaly, C Anomaly, C -40.0 -10.0 20.0 -5.00 0.00 5.00 -5.00 0.00 5.00 -5.00 0.00 5.00 CFSR T2M Anomaly MERRA T2M Anomaly ERA_I T2M Anomaly JRA25 T2M Anomaly Anomaly, C Anomaly, C Anomaly, C Anomaly, C -5.00 0.00 5.00 -5.00 0.00 5.00 -5.00 0.00 5.00 -5.00 0.00 5.00

T2m, Spring Median T2M, Spring, 1980-2009 NCEP_R1 T2M Anomaly NCEP_R2 T2M Anomaly 20CR T2M Anomaly Median, C/yr Anomaly, C Anomaly, C Anomaly, C -40.0 -10.0 20.0 -5.00 0.00 5.00 -5.00 0.00 5.00 -5.00 0.00 5.00 CFSR T2M Anomaly MERRA T2M Anomaly ERA_I T2M Anomaly JRA25 T2M Anomaly Anomaly, C Anomaly, C Anomaly, C Anomaly, C -5.00 0.00 5.00 -5.00 0.00 5.00 -5.00 0.00 5.00 -5.00 0.00 5.00

T2m Annual Temperature Trends T2M, 1980-2009 Annual Trend NCEP_R1 T2M Trend NCEP_R2 T2M Trend 20CR T2M Trend Median, C/decade C/decade C/decade C/decade -0.5 0.0 0.5 -0.5 0.0 0.5 -0.5 0.0 0.5 -0.5 0.0 0.5 CFSR T2M Trend MERRA T2M Trend ERA_I T2M Trend JRA25 T2M Trend C/decade C/decade C/decade C/decade -0.5 0.0 0.5 -0.5 0.0 0.5 -0.5 0.0 0.5 -0.5 0.0 0.5

Downwelling Surface Radiative Fluxes Longwave Bias Shortwave Bias 60 100 40 50 20 W/m2 W/m2 0 0 -20 -50 -40 NCEP_R1 NCEP_R2 20CR CFSR MERRA ERA_I JRA25 -60 -100 2 4 6 8 10 12 2 4 6 8 10 12 Month Month Longwave Correlation Shortwave Correlation 1.0 1.0 0.8 0.8 0.6 0.6 R R 0.4 0.4 0.2 0.2 0.0 0.0 2 4 6 8 10 12 2 4 6 8 10 12 Month Month

Longwave Flux, Winter Median DWLWRFB, Winter, 1980-2009 NCEP_R1 DWLWRFB Anomaly NCEP_R2 DWLWRFB Anomaly 20CR DWLWRFB Anomaly Median, W/m2/yr Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 129 237 346 -16.6 0.0 16.6 -16.6 0.0 16.6 -16.6 0.0 16.6 CFSR DWLWRFB Anomaly MERRA DWLWRFB Anomaly ERA_I DWLWRFB Anomaly JRA25 DWLWRFB Anomaly Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 -16.6 0.0 16.6 -16.6 0.0 16.6 -16.6 0.0 16.6 -16.6 0.0 16.6

Longwave Flux, Summer Median DWLWRFB, Summer, 1980-2009 NCEP_R1 DWLWRFB Anomaly NCEP_R2 DWLWRFB Anomaly 20CR DWLWRFB Anomaly Median, W/m2/yr Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 150 250 350 -20.0 0.0 20.0 -20.0 0.0 20.0 -20.0 0.0 20.0 CFSR DWLWRFB Anomaly MERRA DWLWRFB Anomaly ERA_I DWLWRFB Anomaly JRA25 DWLWRFB Anomaly Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 -20.0 0.0 20.0 -20.0 0.0 20.0 -20.0 0.0 20.0 -20.0 0.0 20.0

Shortwave Flux, Spring Median DWSWRFB, Spring, 1980-2009 NCEP_R1 DWSWRFB Anomaly NCEP_R2 DWSWRFB Anomaly 20CR DWSWRFB Anomaly Median, W/m2/yr Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 150 225 300 -50.0 0.0 50.0 -50.0 0.0 50.0 -50.0 0.0 50.0 CFSR DWSWRFB Anomaly MERRA DWSWRFB Anomaly ERA_I DWSWRFB Anomaly JRA25 DWSWRFB Anomaly Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 -50.0 0.0 50.0 -50.0 0.0 50.0 -50.0 0.0 50.0 -50.0 0.0 50.0

Shortwave Flux, Summer Median DWSWRFB, Summer, 1980-2009 NCEP_R1 DWSWRFB Anomaly NCEP_R2 DWSWRFB Anomaly 20CR DWSWRFB Anomaly Median, W/m2/yr Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 150 225 300 -50.0 0.0 50.0 -50.0 0.0 50.0 -50.0 0.0 50.0 CFSR DWSWRFB Anomaly MERRA DWSWRFB Anomaly ERA_I DWSWRFB Anomaly JRA25 DWSWRFB Anomaly Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 Anomaly, W/m2 -50.0 0.0 50.0 -50.0 0.0 50.0 -50.0 0.0 50.0 -50.0 0.0 50.0

Precipitation

Annual Precipitation Median Annual Precipitation, 1980-2009 NCEP_R1 PRECIP Anomaly NCEP_R2 PRECIP Anomaly 20CR PRECIP Anomaly Median, m/yr Anomaly, m/yr Anomaly, m/yr Anomaly, m/yr 0.00 1.00 2.00 -0.50 0.00 0.50 -0.50 0.00 0.50 -0.50 0.00 0.50 CFSR PRECIP Anomaly MERRA PRECIP Anomaly ERA_I PRECIP Anomaly JRA25 PRECIP Anomaly Anomaly, m/yr Anomaly, m/yr Anomaly, m/yr Anomaly, m/yr -0.50 0.00 0.50 -0.50 0.00 0.50 -0.50 0.00 0.50 -0.50 0.00 0.50

10-m Wind Speed at SHEBA

10-m Wind Speed, Winter Median AVG_SPD, Winter, 1980-2009 NCEP_R1 AVG_SPD Anomaly NCEP_R2 AVG_SPD Anomaly 20CR AVG_SPD Anomaly Median, m/s/yr Anomaly, m/s Anomaly, m/s Anomaly, m/s 2.0 6.0 10.0 -2.00 0.00 2.00 -2.00 0.00 2.00 -2.00 0.00 2.00 CFSR AVG_SPD Anomaly MERRA AVG_SPD Anomaly ERA_I AVG_SPD Anomaly JRA25 AVG_SPD Anomaly No Data Anomaly, m/s Anomaly, m/s Anomaly, m/s -2.00 0.00 2.00 -2.00 0.00 2.00 -2.00 0.00 2.00

Conclusions  2-m Temperature : MERRA does best in bias, MERRA, CFSR, and JRA-25 do well in correlations. Trends are much stronger in the NCEP-R1 and R2 models.  Radiative fluxes : MERRA, CFSR, and ERA-Interim all do well in both bias and correlations.  Precipitation : JRA-25 has the smallest bias. The anomaly correlations is best for ERA-Interim. But MERRA, JRA25, and CFSR. are also good. CFSR is much wetter over the oceans, though not in the Arctic.  Wind speed : NCEP-R2 has a low bias except in winter. All the others have a high bias in winter. Otherwise they do quite well. NCEP-R1 is markedly higher than the others over land.

Seasonal trends vs height for temperatures N of 70N.

Surface Downwelling Longwave Trends, Fall DWLWRFB, Fall, 1980-2009 Trend NCEP_R1 DWLWRFB Trend NCEP_R2 DWLWRFB Trend 20CR DWLWRFB Trend Median W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10 CFSR DWLWRFB Trend MERRA DWLWRFB Trend ERA_I DWLWRFB Trend JRA25 DWLWRFB Trend W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10

Surface Downwelling Longwave Trends, Winter DWLWRFB, Winter, 1980-2009 Trend NCEP_R1 DWLWRFB Trend NCEP_R2 DWLWRFB Trend 20CR DWLWRFB Trend Median W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10 CFSR DWLWRFB Trend MERRA DWLWRFB Trend ERA_I DWLWRFB Trend JRA25 DWLWRFB Trend W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10

Surface Downwelling Longwave Trends, Spring DWLWRFB, Spring, 1980-2009 Trend NCEP_R1 DWLWRFB Trend NCEP_R2 DWLWRFB Trend 20CR DWLWRFB Trend Median W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10 CFSR DWLWRFB Trend MERRA DWLWRFB Trend ERA_I DWLWRFB Trend JRA25 DWLWRFB Trend W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10

Surface Downwelling Longwave Trends, Summer DWLWRFB, Summer, 1980-2009 Trend NCEP_R1 DWLWRFB Trend NCEP_R2 DWLWRFB Trend 20CR DWLWRFB Trend Median W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10 CFSR DWLWRFB Trend MERRA DWLWRFB Trend ERA_I DWLWRFB Trend JRA25 DWLWRFB Trend W/m2 / dec W/m2 / dec W/m2 / dec W/m2 / dec -10 0 10 -10 0 10 -10 0 10 -10 0 10