q 1997 American Meteorological Society Surface Observed Global Land Precipitation Variations during 1900–88

• Main Authors: Aiguo Dai, Inez Y. Fung, Anthony D. Del Genio
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1996
• Subjects: Canada; Greenland; Argentina; North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.587.1289; http://www.cgd.ucar.edu/cas/adai/papers/Precip-JC-97-Paper.pdf

The authors have analyzed global station data and created a gridded dataset of monthly precipitation for the period of 1900–88. Statistical analyses suggest that discontinuities associated with instrumental errors are large for many high-latitude station records, although they are unlikely to be significant for the majority of the stations. The first leading EOF in global precipitation fields is an ENSO-related pattern, concentrating mostly in the low latitudes. The second leading EOF depicts a linear increasing trend (;2.4 mm decade21) in global precipitation fields during the period of 1900–88. Consistent with the zonal precipitation trends identified in previous analyses, the EOF trend is seen as a long-term increase mostly in North America, mid- to high-latitude Eurasia, Argentina, and Australia. The spatial patterns of the trend EOF and the rate of increase are generally consistent with those of the precipitation changes in increasing CO2 GCM experiments. The North Atlantic oscillation (NAO) accounts for;10 % of December–February precipitation variance over North Atlantic surrounding regions. The mode suggests that during high-NAO-index winters, precipitation is above normal in northern (.508N) Europe, the eastern United States, northern Africa, and the Mediterranean, while below-normal precipitation occurs in southern Europe, eastern Canada, and western Greenland. Wet and dry months of one standard deviation occur at probabilities close to those of a normal distribution