Land and ocean surface temperature: data development and modeling

Abstract:

Surface temperature (ST) plays a critical role in land-atmosphere-ocean interactions, and is one of the fundamental variables for Earth system research. ST includes surface air temperature (SAT), surface skin temperature (Ts), and subsurface water or soil temperature at a given depth [T(z)]. In this presentation, we will review our recent work on land and ocean ST.

Over land, we have developed the first global 0.5 deg hourly SAT datasets from 1948-2009 by merging in situ CRU data with reanalysis data. Using these datasets, over high latitudes in winter the monthly averaged diurnal temperature range is found to be much larger than the range of monthly averaged hourly temperature diurnal cycle. The former primarily reflects the movement of synoptic weather systems, while the latter is primarily affected by the diurnal radiative forcing. We have also compared Ts from satellite remote sensing (MODIS) and land modeling (CLM) with in situ measurements. For instance, we have identified five factors contributing to the Ts differences between the model and MODIS.

Over ocean, we have developed a prognostic Ts parameterization for modeling and data analysis. For instance, the inclusion of the Ts diurnal cycle affects atmospheric processes at diurnal, intraseasonal, and longer time scales. Furthermore, our parameterization provides the relationship between water temperature T(z) at different depths and Ts, and hence helps to merge temperature data from satellite infrared and microwave sensors and in situ buoy and ship measurements.