Effects of 2-m air temperature assimilation and a new near-surface observation operator on the NCEP Gridpoint statistical-interpolation system

Abstract

In this study, we assimilate 2-m air temperature data with the National Centers for Environmental Prediction (NCEP) regional Gridpoint Statistical Interpolation (GSI) using the WRF-NMM model forecast as a first guess. Single time analysis experiments are conducted to test the impact of 2-m air temperature data on the analysis system and the results are compared with the control run without using 2-m air temperature data. The effort is focused on understanding the characteristics of observation innovations of the 2-m air temperature data. Modifications to background errors and a simple test of nonlinear quality control are also considered. The incorporation of a comprehensive near-surface observation operator based on Monin-Obukhov similarity theory is described and tested for possible operational use with the NCEP regional GSI system. The results from this new forward operator are compared with those from the existing simple forward operator. According to the results, mesonet 2-m temperature data were found to have a considerable amount of outliers compared with other 2-m temperature data. The nighttime western and central US domains indicated a model warm bias. Stations with large innovations are distributed uniformly in the nighttime western and central domains, while they are mainly located in the large cities in the daytime eastern domain. The statistical analysis of observation innovations showed that introduction of the new forward model can reduce root-mean-square errors in observation increment statistics. The results of a short assimilation experiment indicate that the new forward operator can be employed as a short-term strategy for near-surface data assimilation in the NCEP.

A Statistical Parameter Correction Technique for WRF Medium-Range Prediction of Near-Surface Temperature and Wind Speed Using Generalized Linear Model

“…To clearly address this issue, some geophysics and thermodynamics calculations would be required. However, this is beyond the scope of the present research, and incidentally does not impact the results obtained from the above method, as it is not assimilated in the WRF simulation [29]. On the other hand, the LAMP WRF model deals with medium-range (12-day) predictions, which start from the initial model fields, instead of climate projections.…”

High‐Resolution Regional Reanalysis in China: Evaluation of 1 Year Period Experiments

“…Channels of satellite radiance data ingested by data assimilation system are shown in Table 2. It should be noted that all nearsurface observation data are not assimilated in CNRR because ingesting the near surface observations may 1826,1865,1865,1866,1868,1869,1872,1873,1876,1881,1882,1911,1917,1918,1924,1928 1001~1100 1101~1200 1201~1300 1301~1400 1401~1500 1501~1600 1601~1800 1801~2000 2001~3000 1027, 1046, 11 1121,1133, 1191,1194 1271 1479 1509,1513, 1521,1536, 1574,1579, 1585,1587 1626,1639, 1643,1652, 1658,1671, 1786 1805,1884, 1991 2019,2094, 2119,2213, 2239,2271, 2321,2398, 2701, Journal of Geophysical Research: Atmospheres 10.1002/2017JD027476 cause uncertainties to data assimilation outcomes (Bédard, Laroche, & Gauthier, 2015;Jordi et al, 2015;Lee et al, 2011;Pu, 2017).…”

“…Channels of satellite radiance data ingested by data assimilation system are shown in Table . It should be noted that all near‐surface observation data are not assimilated in CNRR because ingesting the near surface observations may cause uncertainties to data assimilation outcomes (Bédard, Laroche, & Gauthier, ; Jordi et al, ; Lee et al, ; Pu, ).…”

Spatial and Temporal Variation in PBL Height over the Korean Peninsula in the KMA Operational Regional Model

“…The nonlocal YSU boundary layer scheme uses prescribed eddy diffusivity profiles and permits countergradient terms in the situation of convective boundary mixing. Also, as an upgraded version of the MRF PBL scheme [2,38], it considers an explicit representation of entrainment at the top of the boundary layer. Stability functions for momentum and heat are determined according to atmospheric stability that has four regimes based on the critical Bulk-Richardson number (Rib cr ): free convection (Rib cr < 0), forced convection (Rib cr = 0), damped mechanical turbulence (0 < Rib cr < 0.2), and stable atmosphere (Rib cr >= 0.2).…”