Temporal Changes in the Observed Relationship between Cloud Cover and Surface Air Temperature

摘要: The relationship between cloud cover and near-surface air temperature its decadal changes are examined using the hourly synoptic data for past four to six decades from five regions of Northern Hemisphere: Canada, United States, former Soviet Union, China, tropical islands western Pacific. authors define normalized cover‐surface relationship, NOCET ordT/dCL, as a anomaly with unit (one-tenth) deviation total average value. Then mean monthly time series (night- daytime, separately) area-averaged parameterized functions surface humidity snow cover. day- nighttime variations strongly anticorrelated in humidity. Furthermore, daytime positively correlated extent. regionally averaged varies 20.05 K tenth21 wet Tropics 1.0 at midlatitudes winter. regional ranges 20.4 0.7 found general strengthening cooling during post‐World War II period associated over States but minor reduction this higher latitudes. since 1970s, prominent increase atmospheric has significantly weakened effectiveness warming (best seen nighttime) apportion spatiotemporal field interactions into bivariate (described by two equations, one constant factors. These factors invariant space domains. It is speculated that they may represent empirical estimates overall effect on temperature.