Extended Abstract (2.0M)P7.7
An Operational Cloud Verification System and Its Application to Validate Cloud Simulations in Operational Models
Xiaofan Li, JCSDA and NOAA/NESDIS/ORA, Camp Springs, MD; and F. Weng
An operational cloud verification system is being developed at the Joint Center for Satellite Data Assimilation, aiming towards validating the cloud simulations in the operational models and guiding further improvement of the prognostic cloud schemes. The system collects satellite-retrieved cloud products such as liquid water and ice paths (LWP/IWP), precipitable water (PW), surface rain rate, cloud top pressure and temperature, cloud amount and the others from Microwave Surface and Precipitation Products System (MSPPS), Advanced Television InfraRed Observation Satellite (TIROS) Operational Vertical Sounder (ATOVS), Clouds from Advanced Very High Resolution Radiometer (AVHRR) (CLAVR) from Polar Operational Environmental Satellites (POES) and Automated Surface Observing System (ASOS) from Geostationary Operational Environmental Satellites (GOES). The Cloud simulations in NCEP/Global Data Assimilation System (GDAS) are validated with the PW, LWP, and IWP from the MSPPS. The root-mean-square (RMS) differences of the PW between the GDAS and MSPPS are 3 mm over clear-shy regions and 5 mm over cloudy regions respectively. The RMS difference of the PW over cloudy regions has the similar magnitude of the mass-integrated mixing ratios of cloud hydrometeors, indicating that the GDAS may have difficulty to accurately simulate the cloud properties. The further comparison of the LWP/IWP between the GDAS and MSPPS shows that the GDAS simulates unrealistically large IWP. With the help of the cloud-resolving modeling study, the unrealistic ice simulations in the GDAS may be known to be the result of the exclusion of the depositional growth of precipitation ice from non-precipitation ice in the GDAS. Consistence Checks are carried out for same meteorological parameters retrieved from different satellite data as an important part of the system buildup efforts. The cloud top pressures and temperatures retrieved from the POES/ATOVS and GOES/ASOS over the Pacific Tropics show similar horizontal cloud distributions with the high correlation coefficients of 0.8. However, the RMS differences are about 175 mb for the pressure and 15 K for the temperatures. Such significant differences suggest that a caution should be exercised when the cloud products are chosen for the validation purposes. In addition of validation with satellite-retrieved cloud products, the satellite-measured radiances are also used to validate the simulated radiance using the radiative transfer model with the outputs of vertical thermodynamic and cloud profiles from the operational models. More results will be reported in the meeting.
Poster Session 7, Retrievals and Cloud Products: Part 1
Thursday, 23 September 2004, 9:30 AM-11:00 AM
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