UAH Version 6 global satellite temperature products: Methodology and results

• Published in: Asia-Pacific journal of atmospheric sciences 2017, 53(1), , pp.121-130
• Main Authors: Spencer, Roy W., Christy, John R., Braswell, William D.
• Format: Article
• Language: English
• Subjects: Atmospheric Sciences; Climatology; Drift; Earth and Environmental Science; Earth Sciences; Geographical distribution; Geophysics/Geodesy; Lower stratosphere; Methods; Procedures; Satellites; Stratosphere; Temperature; Trends; Tropopause; Troposphere; 대기과학
• ISSN: 1976-7633; 1976-7951
• DOI: 10.1007/s13143-017-0010-y

Version 6 of the UAH MSU/AMSU global satellite temperature dataset represents an extensive revision of the procedures employed in previous versions of the UAH datasets. The two most significant results from an end-user perspective are (1) a decrease in the global-average lower tropospheric temperature (LT) trend from +0.14°C decade −1 to +0.11°C decade −1 (Jan. 1979 through Dec. 2015); and (2) the geographic distribution of the LT trends, including higher spatial resolution, owing to a new method for computing LT. We describe the major changes in processing strategy, including a new method for monthly gridpoint averaging which uses all of the footprint data yet eliminates the need for limb correction; a new multi-channel (rather than multi-angle) method for computing the lower tropospheric (LT) temperature product which requires an additional tropopause (TP) channel to be used; and a new empirical method for diurnal drift correction. We show results for LT, the midtroposphere (MT, from MSU2/AMSU5), and lower stratosphere (LS, from MSU4/AMSU9). A 0.03°C decade −1 reduction in the global LT trend from the Version 5.6 product is partly due to lesser sensitivity of the new LT to land surface skin temperature (est. 0.01°C decade −1 ), with the remainder of the reduction (0.02°C decade −1 ) due to the new diurnal drift adjustment, the more robust method of LT calculation, and other changes in processing procedures.