摘要:

AbstractAn objectively derived catalogue of daily pressure patterns for 1899‐1974 has been prepared for the western United States. The temperature and precipitation characteristics of the major types are described and a more detailed analysis for Colorado in extreme cold and warm months shows that the sign of the anomalies for each type is generally consistent with expectation based on the probable airflow patterns. A regression analysis of type frequencies versus temperature and precipitation anomalies for 1899‐1970 at stations east and west of the Continental Divide in the Rocky Mountain states shows that useful explanation of variance is obtained only for temperatures in the transition seasons and for precipitation west of the Divide in winter and east of the Divide in spring. Within‐type variability of the climatic characteristics is one source of the discrepancy. The results underline the problems encountered in trying to link climatic anomalies with atmospheric circulation characteri

ISSN:0196-1748    

DOI:10.1002/joc.3370010202

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractVariations in rainfall over southern Africa are explained in terms of variations in pressure and circulation patterns. The extended wet spells of the quasi 18‐year oscillation in rainfall that have affected the subcontinent are shown to have occurred in association with increased pressures in the region where the subtropical ridge of the first zonal standing wave in the 500‐mb surface has its expression in the southern hemisphere, in association with the eastwards displacement or weakening of the Indian Ocean high and a probable lowering of pressure over the subcontinental interior. It is further suggested that the 10‐11 year rainfall oscillation of the southern Cape may be forced by longitudinal changes in the position of the first ridge of standing wave 3 which may oscillate with a similar quasi‐peri

ISSN:0196-1748    

DOI:10.1002/joc.3370010203

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractUsing data for a 29‐month period from an intense network of extended scale autographic raingauges at Dar es Salaam, various different storm types are identified, which are thought to be representative of the East African coast as a whole. The primary means of identification of storm types were storm morphology, mode of development and movement. Three major storm groups are proposed: (i) linear storms which develop parallel to the coast along sea or land‐breeze fronts, (ii) smaller elliptical outbreaks developingin situ, and (iii) small, moving elliptical ‘air mass’ storms apparently associated with the prevailing trade wind circulation. A fourth but far less numerous group is composed of large, often heavy, amorphous storms whose origins probably lie with larger‐scale tropospheric perturbations, rather than with loc

ISSN:0196-1748    

DOI:10.1002/joc.3370010204

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe pentad rainfall data of six stations in the Andaman‐Nicobar group of islands for the period 1953‐1978 have been analysed to study the northward advance of the ITCZ and the onset of the summer monsoon rainfall over the southeast Bay of Bengal. It is found that at the island stations south of 10°N the summer monsoon rains set in on the average towards the end of April which is a month in advance of the onset of the monsoon over the south Kerala coast of peninsular India. At the island stations to the north of 10°N the onset occurs about the first week of May. These dates are ahead of those shown in the existing diagrams giving the average onset dates of the summer monsoon over the southeast Bay of Bengal. Examination of the frequency and latitude of formation of cyclonic disturbances in the Bay of Bengal and the progressive seasonal variations of the tropospheric winds over the aerological station of Port Blair during April‐May lend support to the earlier onse

ISSN:0196-1748    

DOI:10.1002/joc.3370010205

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe total volume of rain‐water over India has been computed for each of the years during the period 1871‐1978 on the basis of the rainfall data for a fixed network of 306 raingauges. The mean, the standard deviation and the coefficient of variation of the series of annual rain‐water volume are 3143 km3, 300 km3and 9.5 per cent, respectively. The series is homogeneous and random. The serial correlation is 0.013 which is too low to suggest any relationship between successive terms. Gaussian distribution gives a good fit to the series.The series giving the percentage area of the country with a deficiency of 20 per cent or more, as well as the percentage area with an excess of 20 per cent or more have been obtained. These bring out the variability in the deficiency and excess of rain‐water over the country during the period. The years of well‐marked rain‐water deficiency/excess over India have been identified by utilizing the criterion of 40 per cent or more area under rain‐water deficiency/excess. The occurrence of such years has been found to be random and the number of such years in five‐year periods appears to be distributed in accordance with the Binomial and the Poisson Probability models.The impact of marked deficiency/excess on the All India Index of food grain prices and All India Index of food grain production has been examined. It is found that the impact of well‐marked deficiency can generally be seen clearly but that of well‐marked excess is seen clearly in some cases only. This is understandable. Overall excess in a year may or may not result in floods which have the potentiality to damage crops. The impact of the well‐marked deficiency of 1918 has been maximum.Remedial measures which would make the economy of the country less dependent on the variability of the annual rain‐wa

ISSN:0196-1748    

DOI:10.1002/joc.3370010206

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370010207

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370010208

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370010210

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370010211

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370010212

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY