Homogenizing Surface and Satellite Observations of Cloud
Abstract
Using four months of global surface cloud observations an investigation has been made concerning both types of contingency probability as applied to different cloud levels. Analysis of the probability as applied to different cloud levels. Analysis of the probability of observing an upper cloud given the presence of a lower cloud, P(L approaches U) with varying lower level cloud amounts gives different results from those of Hahn et al. (1982) at a variety of spatial scales ranging from individual stations to the globe. The implications of this are discussed with respect to the probability of observing a lower cloud in the presence of an upper cloud, P(U approaches L). We find that their evaluation of P(U approaches L) is greater than our calculation which is modified to account for the variation in P(L approaches U). Their overestimate is most noticeable in low and middle latitudes and can be reversed (to an underestimate) in some high latitude areas. Plans for the investigations of temporal variations in cloud amount and type on the ocean surface radiation budget are also discussed in the context of the first analysis of the large data set of all-sky camera imagery obtained from the Joint Air Sea Interaction Experiment (JASIN) conducted in 1978. Our results show a considerable temporal variability in total and high cloud amount cf. conventional (bridge) observations. Also we find that the bridge observer often failed to report thin upper-level cloud. This omission, if it is widespread, may also affect the surface-based climatologies of Hahn et al.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1988
- Accession Number
- ADA201630
Entities
People
- Alan H. Goodman
- Ann Henderson-sellers
Organizations
- University of Liverpool