Zaizhong Ma and Lars Peter Riishojgaard

Joint Center for Satellite Data Assimilation & University of Maryland Baltimore County

Michiko Masutani

NCEP Environmental Modeling Center

Wind Lidar OSSEs

OSSEs setup

Initial results Anomaly Correlation coefficients (500hPa Geopotential

Height)

Tropical Wind RMSE (200hPa and 850hPa)

Summary and Future work

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Overview:

Impact experiments carried out as part of NASA-NOAA Joint OSSE collaboration

Common Nature Run supplied by ECMWF

Shared simulation of reference observations; contributions by NESDIS, GMAO, NCEP, et al.

Wind Lidar OSSE project funded by NASA (Kakar and Lee) under ROSES 2007

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Wind Lidar OSSEs:

NCEP GFS coupled with GSI data assimilation system GFS at T-126 horizontal resolution “OSSE period”: July 01-Aug 15 ， 2005 (simulated)

Most observing systems used for routine operational NWP included, except GPSRO and IASI

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Experiment Setup:

Number of lidar observations per analysis cycle (shown only for 00Z)

Total rejection rate around 6%

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Four experiments, all verified against Nature Run CTRL : Assimilating the “observation” from NR, except Lidar wind data NOUV : CTRL without raob (220, 221 and 232) NONW: CTRL without all wind data DWL : CTRL + hybrid Satellite lidar wind data

Experiment Setup (cons):

0118 July0112 July …… 1500 Aug

Cycling experiments with 6h assimilation window from July 01 to Aug 15, 2005

5-day Forecast

5-day Forecast

EXP: CTRL, NOUV, NONW, DWL

Five-day forecast launched every day at 00, 06, 12, 18Z

500hPa HGT anomaly correlation coefficients

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0.8%

NH1.8%

SH

More fine scalesMore fine scales

Time series of 500hPa geopotential height ACNH SH

Day 1

Day 5

Day 3

Candidates for additional study

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NH: 500hPa

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Time series of 500hPa geopotential height AC (con.)

SH: 500hPa

RMSE: 200, 850hPa Wind error in tropics

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200hPa 850hPa

200 hPa 850 hPa

Day 1

Day 5

Day 3

10

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Time series of 200, 850hPa Wind RMSE in tropics

Forecast: Day 1 Forecast: Day 5

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Time series of Wind RMSE in tropics

A comprehensive OSSE system has been developed under the Joint OSSE collaboration

Initial results simulating expected impact of GWOS observations on NCEP GFS system are very encouraging Small positive impact in North Hemisphere (~ 1%)

Larger positive impact in South Hemisphere (~ 2%)

Very large positive impact in tropics

Future work: special case study (shown in Slide 7), increasing horizontal resolutions (T382) …

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Summary and Future work: