BMB-UCAR WRF 3D-Var project

Summary for 26 August – 8 September 2006

Reporting time (for this report): 11 September 2006

 

 

Task 5. Meteorological performance

5.1. BE

 

Shuiyong is preparing data to re-calculate BE using the WRF forecasts during the whole summer of 2006. No specific report for this part.

 

5.2. WRFDFI

 

To solve the problem TDFI has longer spin-up time and lower precipitation rate than NODFI, Min made several tests:

l      No filtering the qvapor and hydrometeors. There is still a lot of noise.

l      Just filtering qv, dpsdt is still noisy.

l      During the backward integration, switch on the microphysics option but skip the calling of module-microphysics driver to make the hydrometeor arrays active.

A.    ThereŐre negative values in hydrometeor arrays from solve_em.

B.     It remove the moist-loops, no advection and diffusion (both explicit and implicit) for hydrometeors, the moisture arrays will be kept identical to these in wrfinput.

Using B for cycle tests, results show that the precipitation rate is still lower than NODFI.

HansŐ suggestions:

l      The negative values of hydrometeor arrays could be caused by the negative filtering coefficients. Make a test with the Lanczos filter.

l      Three options for moisture filtering: 1) Filtering qv and hydrometeors, 2) Save the qv and hydrometeors at t=0 during the forward integration procedure of filtering as the initial value of their filtered results; 3) Take qv and hydrometeors from the analysis (wrfinput).

 

Progress should be reported next time. (Min)

 

5.3. Comparison

 

No report was provided by Zaiwen yet.

Task 6. Monitoring of pre-operational runs and case studies

 

6.1. Verification

 

The codes relating with vertical level verification has been prepared. But further tests will be performed.

 

6.2. OSE

 

According to YongrunŐs suggestion, Jiqin plotted an O-B distribution figure for GPSPW and it implied that the bias error (O-B) of GPSPW violated the assumption of VAR.

 

From previous results, the assimilation of GPSPW data with poor quality could still lead to better forecasted precipitation, which is a little bit inconvincible. Therefore, Jiqin performed a series of experiments to identify the origination of the unreasonable noises existing in the meteorological fields in area with complex topography. It revealed that itŐs the change of IFEED option, not the assimilation of GPSPW that contributed most significantly to the better precipitation.

 

The larger bias of GPSPW (O-B) was just from the real-time GPSPW data as Jiqin reported. There is no problem with the post-processing GPSPW data. Jiqin also said that after 13 August, the real-time GPSPW data are close to the post-processing GPSPW data within difference of 2~3 mm. Jiqing should re-do the real-time GPSPW data experiments (Yong-Run Guo).

6.3. Cycling

 

A cycling script system is ready and the bug of the incompatibility between wrfvar and wrf model has been fixed by Yongrun. Cycling experiments have been performed.

 

However, the work was planned to start in October. No report is required.

 

6.4. Tuning

 

Shuiyong updated the landuse category for WRF model using the latest landuse data with 30-second resolution.

 

The tuning work was planned to start next year. No report is required from Zuofang.

 

6.5. MM5DFI

 

The work was planned to start next year. No report is required.

 

Next report time: 22 September 2006!!