Last April is an interesting month. The http://www.ncdc.noaa.gov/oa/climate/research/2009/apr/global.html#temp" [Broken] ranks last April as the fifth warmest on record. The lower troposphere (<8 kilometers) however is ranked eleventh by RSS and fifteenth by UAH. Why the large discrepancy? Should we expect the surface temperature (< 1.5 meters) ranking to correlate somewhat with the lower troposphere?