2008), which will take ship and you will buoy measurements and you may provides good gridded dataset on 2° quality having fun with a maximum interpolation strategy. I utilize the climatological research computed between 1981 and you can 2010. Just like the good metric to your interhemispheric variation regarding exotic SST, we calculate ?SST because the spatially adjusted SST amongst the equator and you will 20°N without having the spatially weighted SST between your equator and 20°S. 1
(iii) Atmospheric temperature transport along the equator
The newest atmospheric temperature transport hails from new Federal Centers to have Ecological Anticipate (NCEP) four-times-day-after-day reanalysis fields (Kalnay mais aussi al. 1996) with a great (horizontal) spectral solution out of T62 and you may 17 straight levels. Brand new atmospheric temperatures transportation is determined because of the very first milf free controlling brand new atmospheric size finances throughout the reanalysis studies that have good barotropic cinch modification like in Trenberth (1997) and you can then calculating the new meridional flux away from moist fixed opportunity 2 and you can vertically integrating. This procedure is employed to write month-to-month averaged atmospheric temperature transport out of 1981 to help you 2010 as well as the climatological average more this era is used in this studies.
We use longwave and shortwave radiative fluxes from the Clouds and Earth’s Radiant Energy System (CERES) experiment (Wielicki et al. 1996) to calculate ?SWABS? and ?OLR?. All calculations are performed separately for each of the four CERES instruments (FM1 and FM2 on Terra from 2000 to 2005 and FM3 and FM4 on Aqua from 2002 to 2005). We then average the results over the four instruments. The quantity ?STORatmos? is calculated as the finite difference of the vertically integrated temperature and specific humidity from the NCEP reanalysis climatology. As in Donohoe and Battisti (2013), ?SHF? is calculated as the residual of radiative heating, atmospheric storage, and the atmospheric heat transport divergence (from NCEP reanalysis).
The new seasonal amplitude and you will stage included in our very own investigation try discussed as the amplitude and phase of the annual harmonic.
A scatterplot of the monthly average PPenny versus AHTEQ and ?SST is shown in Fig. 3. The precipitation centroid varies from 5.3°S in February to 7.2°N in August and has an annual average of 1.65°N. This seasonal cycle of ITCZ location is slightly damped (equatorward) of other common metrics of ITCZ location (e.g., the latitude of maximum zonal mean precipitation, Xian and Miller 2008). It can be seen that PPenny spends four months of the year in the Southern Hemisphere during the austral summer as the most intense precipitation is found in the South Pacific convergence zone at this time of year (not shown) and the zonal mean precipitation maximum moves to southern latitudes. We note that although the marine ITCZ defined in the eastern Pacific and Atlantic by Waliser and Gautier (1993) never moves south of the equator, the global ITCZ defined in the same study does move into the Southern Hemisphere and agrees very well with our precipitation centroid.
(top) Scatterplot of your own seasonal course regarding exotic rain centroid against mix-equatorial atmospheric temperatures transportation. Per get across is actually according to the monthly mediocre in addition to size of the cross on every axis stands for the latest 95% depend on period assessed in the interannual variability. New filled container ‘s the annual average. The dashed line ‘s the linear most useful fit into monthly averages. (bottom) As the during the ideal, but also for the new tropical rain centroid versus the interhemispheric difference in tropical SST.
(top) Scatterplot of one’s seasonal period off tropical precipitation centroid versus mix-equatorial atmospheric heat transport. For each mix are considering the fresh new month-to-month mediocre additionally the length of one’s get across on each axis signifies the newest 95% believe interval assessed throughout the interannual variability. The fresh occupied box is the annual mediocre. This new dashed line ‘s the linear better match into month-to-month averages. (bottom) As within top, but also for new warm precipitation centroid vs the latest interhemispheric difference in tropical SST.