LBM模式中中纬度大气对热源和涡度强迫的响应(英文)

Mid-latitude atmospheric responses to heat and vorticity forcing using a linear baroclinic model

Based on diagnostic analysis of reanalysis data for 58-year,the distribution characteristics of decadal variability in diabatic heating,transient eddy heating and transient eddy vorticity forcing related to the sea surface temperature(SST)anomalies over the North Pacific,as well as their relationship with anomalous atmospheric circulation have been investigated in this paper.A linear baroclinic model(LBM)was used to investigate atmospheric responses to idealized and realistic heat and vorticity forcing anomalies,and then to compare relative roles of different kinds of forcing in terms of geopotential height responses.The results illustrate that the responses of atmospheric height fields to the mid-latitude heating can be either baroclinic or barotropic.The response structure is sensitive to the relative horizontal location of heating with respect to the background jet flow,as well as to the vertical profile of heating.The response to the idealized deep heating over the eastern North Pacific,mimicking the observed heating anomaly,is baroclinic.The atmospheric response to the mid-latitude vorticity forcing is always barotropic,resulting in a geopotential low that is in phase with the forcing.The atmospheric responses to the realistic heat and vorticity forcing show the similar results,suggesting that diabatic heating,transient eddy heating and transient eddy vorticity forcing can all cause atmospheric anomalies and that the vorticity forcing plays a relatively more important role in maintaining the equivalent-barotropic structure of geopotential height anomalies.

Based on diagnostic analysis of reanalysis data for 58-year, the distribution characteristics of decad- al variability in diabatic heating, transient eddy heating and transient eddy vorticity forcing related to the sea sur- face temperature（SST） anomalies over the North Pacific, as well as their relationship with anomalous atmospheric circulation have been investigated in this paper. A linear baroclinic model （LBM） was used to investigate atmos- pheric responses to idealized and realistic heat and vorticity forcing anomalies, and then to compare relative roles of different kinds of forcing in terms of geopotential height responses. The results illustrate that the responses of atmos- pheric height fields to the mid-latitude heating can be either baroelinic or barotropic. The response structure is sen- sitive to the relative horizontal location of heating with respect to the background jet flow, as well as to the vertical profile of heating. The response to the idealized deep heating over the eastern North Pacific, mimicking the ob- served heating anomaly, is baroclinie. The atmospheric response to the mid-latitude vorticity forcing is always baro- tropic, resulting in a geopotential low that is in phase with the forcing. The atmospheric responses to the realistic heat and vorticity forcing show the similar results, suggesting that diabatic heating, transient eddy heating and tran- sient eddy vorticity forcing can all cause atmospheric anomalies and that the vorticity forcing plays a relatively more important role in maintaining the equivalent-barotropic structure of geopotential height anomalies.