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An observationally based evaluation of WRF seasonal simulations over the Central and Eastern Pacific
Author(s) -
Wu Longtao,
Li J.L. F.,
Pi ChiaJung,
Yu JiaYuh,
Chen JenPing
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd023561
Subject(s) - intertropical convergence zone , environmental science , climatology , shortwave , troposphere , weather research and forecasting model , longwave , middle latitudes , outgoing longwave radiation , graupel , atmospheric sciences , climate model , snow , precipitation , cloud cover , convection , geology , radiative transfer , meteorology , climate change , geography , oceanography , cloud computing , physics , quantum mechanics , computer science , operating system
This study uses multiple satellite data sets to evaluate seasonal simulations of the Weather Research and Forecasting (WRF) model over Central and Eastern Pacific. Experiments with five different convective parameterizations all show reasonably good performance for precipitation simulations. However, large discrepancies exist in the model‐simulated ice clouds compared to CloudSat observations. Underestimations of ice clouds, mainly snow and graupel, are present in the Intertropical Convergence Zone (ITCZ) in all the experiments compared to CloudSat. In the ITCZ, all the experiments show a systematic overestimation of outgoing longwave radiation at the top of the atmosphere and downward shortwave radiation at the surface, along with biased cloud cooling in the middle and upper troposphere and biased cloud warming in the lower troposphere. Vertical motion is enhanced in the ITCZ compared to reanalysis. A weaker low‐level circulation over the midlatitude oceans is evidenced in all simulations with an eastward overextension of the South Pacific Convergence Zone and overestimated moisture over the Southern Hemisphere oceans when compared to Special Sensor Microwave/Imager observations. Sensitivity experiment demonstrates that doubling the radiative effect of snow can reduce high biases in vertical motion within the ITCZ and improve the large‐scale circulation and moisture over the midlatitude oceans.