There is considerable interest in interannual climate variations over the globe, as well as concern about the possibility of anthropogenic climate change. For the past five years, the Climate Prediction Center (CPC) has produced an annual Climate Assessment designed to provide a timely summary of both the short-term climate system and of longer-term climate variations. This article is the first of this series to appear in the Bulletin of the American Meteorological Society.
This Annual Assessment documents global-scale climate variations and trends, the evolution of recent oceanic and atmospheric anomalies in the global tropics, and selected regional climate variations. A discussion of global atmospheric temperatures, trace gases and the cryosphere is found in section 2. In section 3, the large-scale conditions in the tropics between 1990 and 1994 are described, followed by a discussion of the transition from warm episode to cold episode conditions in the Pacific during 1995. Section 4 documents regional climate highlights during the past year, including the Indian Monsoon, African rainfall, and notable short-term climate events in the extratropics. Finally, section 5 shows seasonal maps for temperature anomalies, precipitation percentiles and 500-hPa heights and anomalies. These maps are included to continue the set of maps which have appeared in the previous five Annual Climate Assessments.
There are a variety of data sources used in the compilation of this Assessment. The surface data are from preliminary reports obtained over the operational Global Telecommunications System (GTS). Owing to the nature of such reports, the data have not been subject to strict quality control and validation procedures. However, based on past experience we do not expect significant qualitative changes to these preliminary results as more data are accumulated. Other data sources include satellites, radiosonde and ship reports, and gridded analyses from the National Center for Environmental Prediction (NCEP) operational Global Data Assimilation System (GDAS) and from the NCAR/NCEP Climate Data Assimilation System (CDAS)/Reanalysis Project. Selected analyses were also obtained from international climate data centers.
A companion article, to be published in the Journal of Climate, will provide a more detailed diagnostic description of major oceanic and atmospheric anomalies observed during 1995. That annual article will replace the Seasonal Climate Summaries, which have appeared previously in the Monthly Weather Review and more recently in the Journal of Climate.