The 15th BMB-NCAR Project MeetingThe Fifteenth BMB-NCAR Project Meeting

Time: 02:00~03:30 pm, Jan 3, 2006

Participants: Dr. Huang, Dr. Guo, Jiqin Zhong

1. Discuss the project progress

Jiqin had completed the code modification and job script needed by assimilating local data with the WRFVAR system. A series of experiments were carried out to test the performances of assimilation of AWS and GPSPW data respectively. All experiments were completed successfully. The impact of local data on forecasts was found. Whether the impact is positive or negative and to what extend could not be assessed before the verification system is set up. The work on assimilating profiler data should be done by the next meeting.

Dr. Guo suggested Jiqin go deeper into the core of 3DVAR system instead of just running experiments with it. He advised Jiqin not be anxious to run the whole model and acquire the forecast results. Jiqin should analyze the analysis increments first and make sure they are reasonable before running forecasts.

Dr. Guo also suggested Jiqin do experiments to see if there is difference in analysis increments when sfc_assi option is set to 1 and 2 respectively in the case of only AWS data is ingested. Now sfc_assi option is set to 1 in WRFVAR system and there are problems with the option 2. Considering there is no problem with the option 2 in MM5 3DVAR system in KMA, two experiments should be done to check if the analysis increments are similar when the AWS data assimilated using MM5 3DVAR system and using WRFVAR system, respectively, while the cv_options was set to 2 in both experiments.

Dr. Guo proposed that Jiqin try to implement the observation operator of GPS ZTD in WRF-Var using the code from WRF3DVAR. The work may help Jiqin understand the WRF3D-VAR code.

Jiqin found that the observation of certain station would be rejected when relative humidity observed at that station existed in the ‘obs_r_yyyymmddhh’ file during 3DVAR_OBSPROC while she run experiments to assimilate GPSPW data and AWS data. Dr. Guo explained there was no need of relative humidity during the assimilation of GPSPW for existence of precipitation water. He would take time off to check what would be the reason of rejection of AWS data due to the relative humidity.

Dr. Huang suggested Jiqin prepare to assimilate wind profiler data before she gets the verification package. Once the package is ready, Jiqin should focus on the verification tasks.

2 Make a task list

l Jiqin should prepare to assimilate the profiler data and then analyze the analysis increments to ensure the reasonable impact of the data.

l Jiqin should read and understand the ZTD code provided by Dr. Guo.

l Jiqin should focus on the verification tasks once she gets the code.

3 Next meeting

The next meeting will be at 2:00 pm, Jan 17, 2006.