Search Results
some cases, adaptive observing by aircraft may not be feasible, and other adaptive observing system components, such as additional or off-time radiosondes, or high-density satellite winds, may be better suited for sampling these sensitive regions. These results are consistent with those found for the Atlantic ( Reynolds et al. 2007 ), where storms with significant nonlocal sensitivity were often sensitive to changes in the initial state to the northwest of the storm, usually over North America. As
some cases, adaptive observing by aircraft may not be feasible, and other adaptive observing system components, such as additional or off-time radiosondes, or high-density satellite winds, may be better suited for sampling these sensitive regions. These results are consistent with those found for the Atlantic ( Reynolds et al. 2007 ), where storms with significant nonlocal sensitivity were often sensitive to changes in the initial state to the northwest of the storm, usually over North America. As
roughly half as large as those assigned to AMV wind super-obs at similar pressure levels. 3. Experimental design To test the model forecast impact of the RS winds, we designed four experiments, summarized in Table 1 . In all experiments, satellite wind observations are assimilated as super-obs. The control forecast (CNO) uses only the regular (e.g., “operational”) satellite wind data (AMVs), and no AMVs are used over the land area of North America. In a variation of the control, called experiment CNL
roughly half as large as those assigned to AMV wind super-obs at similar pressure levels. 3. Experimental design To test the model forecast impact of the RS winds, we designed four experiments, summarized in Table 1 . In all experiments, satellite wind observations are assimilated as super-obs. The control forecast (CNO) uses only the regular (e.g., “operational”) satellite wind data (AMVs), and no AMVs are used over the land area of North America. In a variation of the control, called experiment CNL
various types of analysis error variance norm decrease discrepancies between target areas computed using SVs and ETKF. By using uncertainty and dynamics information, analysis error variance SVs produce relatively similar sensitive regions with respect to ETKF. Recurving TCs in the western Pacific have much influence on the short-term weather forecasts in East Asia and the medium-range weather forecasts of the North America through extratropical transition. The influence of the midlatitude trough on
various types of analysis error variance norm decrease discrepancies between target areas computed using SVs and ETKF. By using uncertainty and dynamics information, analysis error variance SVs produce relatively similar sensitive regions with respect to ETKF. Recurving TCs in the western Pacific have much influence on the short-term weather forecasts in East Asia and the medium-range weather forecasts of the North America through extratropical transition. The influence of the midlatitude trough on
northeast–southwest-oriented dipole centered on the TC similar to the single increment shown in Fig. 3a ( Fig. 4a ). The second EOF, which explains 23% of the variance, also exhibits a dipole centered on the TC, with a different orientation than the leading EOF (not shown). The third EOF ( Fig. 4b ), as well as the remaining two statistically significant EOFs (e.g., North et al. 1982 ), explain less than 9% of the variance and are generally related to TC intensity. Repeating the calculation, and
northeast–southwest-oriented dipole centered on the TC similar to the single increment shown in Fig. 3a ( Fig. 4a ). The second EOF, which explains 23% of the variance, also exhibits a dipole centered on the TC, with a different orientation than the leading EOF (not shown). The third EOF ( Fig. 4b ), as well as the remaining two statistically significant EOFs (e.g., North et al. 1982 ), explain less than 9% of the variance and are generally related to TC intensity. Repeating the calculation, and
. , 131 , 3409 – 3425 . Langland , R. H. , and Coauthors , 1999a : The North Pacific Experiment (NORPEX-98): Targeted observations for improved North American weather forecasts. Bull. Amer. Meteor. Soc. , 80 , 1363 – 1384 . Langland , R. H. , R. Gelaro , G. D. Rohaly , and M. A. Shapiro , 1999b : Targeted observations in FASTEX: Adjoint based targeting procedures and data impact experiments in IOP/7 and IOP/8. Quart. J. Roy. Meteor. Soc. , 125 , 3241 – 3270 . Lorenz , E. N
. , 131 , 3409 – 3425 . Langland , R. H. , and Coauthors , 1999a : The North Pacific Experiment (NORPEX-98): Targeted observations for improved North American weather forecasts. Bull. Amer. Meteor. Soc. , 80 , 1363 – 1384 . Langland , R. H. , R. Gelaro , G. D. Rohaly , and M. A. Shapiro , 1999b : Targeted observations in FASTEX: Adjoint based targeting procedures and data impact experiments in IOP/7 and IOP/8. Quart. J. Roy. Meteor. Soc. , 125 , 3241 – 3270 . Lorenz , E. N
. , 18 , 172 – 191 . Langland , R. H. , and N. L. Baker , 2004 : Estimation of observation impact using the NRL atmospheric variational data assimilation system. Tellus , 56A , 189 – 201 . Langland , R. H. , and Coauthors , 1999 : The North Pacific Experiment, NORPEX-98: Targeted observations for improved North American weather forecasts. Bull. Amer. Meteor. Soc. , 80 , 1363 – 1384 . Leutbecher , M. , 2003 : A reduced rank estimate of forecast error variance changes due to
. , 18 , 172 – 191 . Langland , R. H. , and N. L. Baker , 2004 : Estimation of observation impact using the NRL atmospheric variational data assimilation system. Tellus , 56A , 189 – 201 . Langland , R. H. , and Coauthors , 1999 : The North Pacific Experiment, NORPEX-98: Targeted observations for improved North American weather forecasts. Bull. Amer. Meteor. Soc. , 80 , 1363 – 1384 . Leutbecher , M. , 2003 : A reduced rank estimate of forecast error variance changes due to
