Precipitation over the North Atlantic Ocean

Abstract

In answer to the last question, I would say that it would require energy of the order 1025-i026 ergs to produce the water vapour observed in the middle stratosphere. Krakatoa is estimated to have released N loz7 ergs so that if one assumes a residence time of the order of centuries (which may not be too unreasonable, having regard to the observed hold-up of W,,, over the equator), this idea may be tenable. I would be happier, though, if Krakatoa had released 1028-1029 ergs.( left uncertain, I should like to suggest that it could be explained by the long track over warm water followed by the air currents before entering the rain-producing depressions. Presumably the patterns of warm and cold water, as affecting evaporation, could produce inequalities in the distribution of rainfall at sea much as relief does on land, although not, perhaps, quite to the same extent.After reading Dr. Tucker's paper I was much perplexed by his A and B stations as bearing on orographic precipitation. Naturally, one would not expect orographic movement in flat islands like Tiree and Benbecula, far from high ground, though some other stations in the A group are quite near higher ground. But why should Mildenhall in the B group be expected to have an orographic effect when it lies in flat country with an average annual rainfall of only 21in., well away from the boulder clay plateau of West Suffolk which is sufficiently high to carry a rainfall of about 26 in.? Apparently, therefore, Mildenhall should lie in rain-shadow of this plateau to the south-west, with a negative orographic factor. It seems particularly desirable to clear up this issue because in Dr. Tucker's Table 4, Mildenhall has the largest error after Blackbushe, which on his own showing is out of keeping with small orographic effect. Lastly, I should like to raise the general question of whether the ocean as a whole, occupying some five-eighths of the surface of the globe, receives more water back from direct rainfall or from the in-flowing rivers. In view of the great intensity and persistence of orographic rainfall and of the many high mountain ranges which border the ocean I would hazard the guess that land drainage into the sea accounts for the larger proportion.Dr. R. C. RAINEY : In view of the very great interest of such estimates of precipitation for other ocean areas, Dr. Tucker might care to comment on a possible limitation of his method (and particularly of its geographical extension) which is not explicitly mentioned in his paper. It is the possibility that the rates of precipitation encountered in some sea areas might differ systematically from those described by the same present-weather code number at the land stations used for the determination of x, y and z. Might one not expect the intensity of ' heavy precipitation,' in particular, to show some systematic geographical variation, in association with, e.g., sea temperature? Warm and cool ocean currents might be envisaged as introducing possible complications, analogous to the orographic effects shown by land st...

Comparing 20 years of precipitation estimates from different sources over the world ocean

“…edu/~climate). Legates and Willmott have used the method developed by Tucker (1961). This method uses the present weather information of standard ship reports and relates it to precipitation rates according to a regression formula.…”

Heat and Freshwater Transport through the Central Labrador Sea*

“…The former values are inferred from precipitation measurements over land in neighboring regions. The latter estimate is based on in situ observations of weather conditions (at OWSB from 1949 to 1972) using Tucker's (1961) algorithm to infer precipitation. Evaporation is estimated from the latent heat flux data and is thus susceptible to errors in the latent heat flux algorithm.…”

Description and evaluation of the bergen climate model: ARPEGE coupled with MICOM

“…Evaporation is estimated using bulk formulas in both cases. In the da Silva dataset the precipitation is derived from Present Weather (PW) information of standard ship reports (Tucker 1961;Dorman and Bourke 1978), while the Oberhuber dataset is based on land and island station records complemented by satellite observations (Shea 1986). As seen from Fig.…”