Amplitude-Phase Characteristics of the Annual Cycle of Surface Temperature: Comparison of AGCM Output and Reanalysis Data

摘要

The amplitude-phase characteristics (APCs) of the annual cycle (AC) of surface air temperature (SAT) were analyzed for output of the MGO,HMC-T21,HMC-T42,INM,and HadAM3 atmospheric general circulation models run with the sea surface temperature variations recommended in the AMIP and AMIP2 projects.The characteristics computed were compared with the NCEP/NCAR and ERA reanalysis data over 1958-1998 and 1979-1993,respectively.The reanalysis data were used to detect the features of SAT AC APCs averages and their variability in various regions,including areas near the snow-ice boundary and regions affected by atmospheric centers of action.Overall,the two reanalyses were found to be similar to each other outside the high latitudes of both hemispheres.The spatial features of SAT AC APCs over land are generally reproduced by the models considered.The models with a warmer annual mean climate (compared with the reanalysis data) exhibit smaller amplitudes of annual and semiannual harmonics and (in the extratropics) later fall and spring phases of the SAT annual cycle.The models with higher (lower) long-term-averaged amplitudes of annual and semiannual harmonics are characterized by higher (lower) interannual rms deviations of these variables.The largest deviations of the simulated SAT AC APC fields from the reanalysis data are observed over the high-latitude land regions in the Northern Hemisphere and over the land and ocean in the Antarctic region.Overall,the models better reproduce the long-term-averaged SAT AC APC fields than their interannual rms deviations.In the annual-cycle characteristics analyzed,the largest differences from the reanalysis data are observed in the amplitude of the semiannual harmonic,the fall and spring phase times,and the interval of exceeding.