FIGURE 5.2 Climate observations come from a diverse system of instruments and are spatially and/or temporally incomplete. Meshing them with global climate models to produce a best estimate of the state of the climate at a given point in time can enhance the value of diverse climate observations. The top image shows atmospheric observations assimilated into GEOS-5 for a typical 6-hour assimilation window. The bottom image shows the daily distribution of ocean observations throughout 1 month (September 2011). AIRS/IASI, Atmospheric Infrared Sounder/Infrared Atmospheric Sounding Interferometer; AMV, Atmospheric Motion Vector; ATOVS, Advanced TIROS (Television Infrared Observation Satellite) Operational Vertical Sounder; GPSRO, Global Positioning System Radio Occultation; TMI, TRMM (Tropical Rainfall measuring Mission) Microwave Imager; XBT, expendable bathythermograph; TAO, Tropical Atmospheric-Ocean; PIRATA, Prediction and Research Moored Array in the Atlantic; RAMA, Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction; CTD, conductivity temperature depth; SLA, sea-level anomaly. SOURCE: Courtesy of Michele Rienecker, NASA.