Annual and interannual variations of absorbed solar radiation based on a 10-year data set

Annual and interannual variations of absorbed solar radiation (ASR) are studied using the 10-year Earth radiation budget data set from the Nimbus 6 and 7 Earth radiation budget instruments in the form of monthly averaged maps of ASR. Empirical orthogonal functions (EOFs) are computed for the global distribution of ASR. Six EOFs are found which have physical significance and which account for 97.8% of the spatial variance of the data set. The first EOF describes the annual cycle and is primarily a latitudinal variation which is driven by the incident solar radiation. The second and fourth EOFs are semiannual cycles. EOFs 3 through 6 are strongly longitudinally dependent. EOF 3 describes the spring/fall part of the annual cycle, and EOF 4 describes the part of the semiannual cycle which is out of phase with EOF 2. EOF 5 is the response of the ASR to El Nino. The annual cycle and its harmonics account for 97.6% of the variance with time. When the data set is deseasonalized, the first two EOFs of the resulting set are found to correspond closely to EOFs 5 and 6 of the data set with season included. As with outgoing longwave radiation, most of the interannual variation is found over the tropical oceans.

[1]  J. Wallace,et al.  Teleconnections in the Geopotential Height Field during the Northern Hemisphere Winter , 1981 .

[2]  John E. Kutzbach,et al.  Empirical Eigenvectors of Sea-Level Pressure, Surface Temperature and Precipitation Complexes over North America , 1967 .

[3]  G. Smith,et al.  Deconvolution of Wide-Field-of-View Measurements of Reflected Solar Radiation , 1990 .

[4]  Ingemar Holmström,et al.  Analysis of time series by means of empirical orthogonal functions , 1970 .

[5]  Robert F. Cahalan,et al.  Sampling Errors in the Estimation of Empirical Orthogonal Functions , 1982 .

[6]  H. Lee Kyle,et al.  The Nimbus-7 Global Cloud Climatology. , 1988 .

[7]  H. Diaz,et al.  An Analysis of the 1877–78 ENSO Episode and Comparison with 1982–83 , 1986 .

[8]  H. Lee Kyle,et al.  The Earth Radiation Budget (ERB) experiment - An overview , 1984 .

[9]  A. F. Krueger,et al.  Annual and Interannual Variations in Outgoing Longwave Radiation over the Tropics , 1981 .

[10]  T. F. Eck,et al.  Nimbus-7 global cloud climatology. I - Algorithms and validation , 1988 .

[11]  J. Wallace,et al.  Empirical Orthogonal Representation of Time Series in the Frequency Domain. Part I: Theoretical Considerations , 1972 .

[12]  C. Eugene Buell.  The Number of Significant Proper Functions of Two-Dimensional Fields , 1978 .

[13]  G. Smith,et al.  Atlas of Wide-Field-of-View Outgoing Longwave Radiation Derived From Nimbus 6 Earth Radiation Budget Data Set- , 1987 .

[14]  P. Ardanuy,et al.  A calibration adjustment technique combining ERB parameters from different remote sensing platforms into a long‐term data set , 1984 .

[15]  P. Ardanuy,et al.  El Nino and outgoing longwave radiation: An atlas of Nimbus-7 Earth radiation budget observations , 1986 .

[16]  John M. Wallace,et al.  Planetary-Scale Atmospheric Phenomena Associated with the Southern Oscillation , 1981 .

[17]  T. Haar,et al.  A comparison of two major Earth radiation budget data sets , 1990 .

[18]  A. Drummond,et al.  Nimbus-6 earth radiation budget experiment. , 1977, Applied optics.

[19]  P. Ardanuy,et al.  El Niño and Outgoing Longwave Radiation: Observations from Nimbus-7 ERB , 1986 .