ISSN:0196-1748    

DOI:10.1002/joc.3370010102

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractLong‐term changes of temperature and of characteristic circulation patterns over the British Isles have been studied using catalogues of daily Central England temperature and daily Lamb circulation types for 1861 to date. Most inter‐decadal temperature variability appears to have been linked with fluctuations in circulation. For given Lamb circulation types much of the observed long‐term variability of temperature appears to derive from lack of precision in the circulation classifica

ISSN:0196-1748    

DOI:10.1002/joc.3370010103

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe relation between the duration of sunshine hours and radiation derived from ten years of daily records at Eskdalemuir and Cawood differs significantly from formulae in general use with the Penman formula. When used in the Penman formula with meteorological data from North East England evaporation estimates were more satisfactory than those based on commonly used formulae. While winter months showed different relations between sunshine and radiation their use in estimating evaporation made no significant difference on cumulative evaporation over a year. The regressionR/RA= 0.1894‐0.624(n/N) derived from Eskdalemuir is satisfactory for use in North East Englan

ISSN:0196-1748    

DOI:10.1002/joc.3370010104

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractA satellite‐derived climatology of cloud vortices for the Southern Hemisphere winter (June to September) indicates that significant within‐season changes occur in the areal frequencies of extratropical depressions. This variability is found to be most strongly associated with the climatic frontal zones, while on a zonally‐averaged basis, the semi‐annual oscillation of the circumpolar vortex appears to dominate the latitudinal changes in cyclonic activity between June and September. Surface‐atmosphere interactions evidently play a key role in the wintertime circulation at middle and high latitudes. Cyclogenesis over the Southern Oceans is observed to be linked closely to the baroclinity associated with the Oceanic Polar Front, while on a regional scale, the presence of a time‐averaged zone ofin situcyclogenesis over sub‐antarctic latitudes of the South Pacific is found to be augmented by the influence of the unique winter season sea ice regime i

ISSN:0196-1748    

DOI:10.1002/joc.3370010105

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractA climatological study of the North Pacific Oscillation (NPO) during Januaries and winters (D‐J‐F) between 1906 and 1978 is presented. The NPO is defined in terms of opposition in sign of mean temperature anomaly between western Alaska‐eastern Siberia (as represented by the stations at Dutch Harbor and St. Paul, Alaska) and western Canada (as represented by Edmonton). The two oscillation modes, Aleutians below normal temperature (Edmonton above normal) and Aleutians above normal temperature (Edmonton below normal), are associated with variations in the strength of the zonal westerlies over the Pacific and North America which in turn result from longitudinal variations in the mean position of the Aleutian low. A westward location of the mean low. over the Sea of Okhotsk, is associated with the development of intense mean high pressure cells over western North America while zonal flow is associated with a more eastward location of the mean low over the Gulf of Alaska. Significant spatial correlations exist between the strength of the zonal component of the geostrophic wind over the Pacific Ocean and the zonal component of the polar and subtropical easterlies over the Pacific sector.The NPO modes are associated with large regional variations in air temperature and precipitation over North America, sea surface temperatures in the North Pacific, and Bering Sea ice. The NPO is found to resemble the second eigenvector of January and winter sea level pressure anomalies. In contrast to its more frequently occurring counterpart, the North Atlantic Oscillation, the NPO is not clearly associated with hemispheric mean temperature trends and its modes occur randomly with time. The two oscillations represent separate patterns of teleconnections of sea level pressure and zonal geostrophic winds over the Northern Hemis

ISSN:0196-1748    

DOI:10.1002/joc.3370010106

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe start of the rains is defined as the first occurrence of a specified amount of rain within two successive days. The probability distribution of the date of the start of the rains is derived from the rainfall models of Stern (1980a). The probabilities of occurrence of dry spells are used to define an earliest practical starting date. Results are presented for eleven stations on a N‐S transect in West Africa. The variation in starting date with latitude is described. Advantages of the model approach over conventional analyses are discusse

ISSN:0196-1748    

DOI:10.1002/joc.3370010107

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractSpatial correlation analysis has been applied to Namib rainfall, in an attempt to identify possible patterns of the spatial organization of localized storms in this area. The utility of the above technique for areas with only sparse raingauge networks is explained. Results indicate that convective storms arenotrandomly scattered in space but, tend to form at preferred distances from each other, around 40‐50 and 80‐100 km, with no preferred locations of, or directions between, storms. Benard cells are mentioned as possibly imposing the inferred organization of convective storms in sp

ISSN:0196-1748    

DOI:10.1002/joc.3370010108

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe agricultural economy of India depends on the regularity of the summer monsoon rains although this climatic phenomenon exhibits a natural variability which often brings disaster. There exists much literature which discusses the physical mechanisms of the monsoon in its general aspects and some attention has been given to explanations of the variability of its main characteristics. Global circulation models afford an opportunity to examine the role of each of many physical components while allowing for interaction between the planetary circulation, sometimes even the oceanic circulation, and the monsoonal one over South Asia. Experiments to date have investigated the influence of Arabian Sea and Indian Ocean surface temperature anomalies, the influence of the Himalayan Mountains, of surface albedo and of the relative importance of sensible versus latent heating in maintaining the summertime regime. Armed with a greater understanding of the causes of monsoon variability, researchers will perhaps be able to begin developing techniques for seasonal forecasting.

ISSN:0196-1748    

DOI:10.1002/joc.3370010109

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370010111

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370010112

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY