摘要:

AbstractAn objective method of drawing climatological maps of sunshine, temperature, rainfall percentage and rainfall amount, which is used operationally at the Irish Meteorological Service in Dublin, is described. The interpolation is based on McLain's method of distance weighted least squares quadratic approximation. The observations are interpolated directly to a regular (rectangular) mesh, without the use of a first‐guess, and the resultant field is contoured and shaded using a standard contouring package.This basic interpolation gave some spurious results near the coast and in data void areas when it was applied in its original form. These problems were overcome by the introduction of dummy values in such regions and a method was developed for calculating such values automatically based on nearby observations and various climatological normals.The method has been in operational use since February 1985 and the results are of quality comparable to the manual method which this computer method has replace

ISSN:0196-1748    

DOI:10.1002/joc.3370080202

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractFive synoptic sequences in the Polar Basin are studied on a day by day basis. A diagnostic model is used to illustrate the relative roles of the dynamic properties of the advected air flow in comparison to mechanisms related to the characteristics of the underlying surface. It is found that the properties of the advected air flow are the major contribution to the vertical circulation associated with synoptic evolution and are a necessary condition. Latent heat release may also be a significant mechanism which supports the proposal by others that a CISK type process may contribute to further development in the Arctic. The surface sensible heat flux is not a necessary process and it may at times oppose the vertical circulation when warm air is advected into the region of development within the circulation of the depression. The surface frictional effect is a minor contribution within the central Polar Basin but is a significant process in systems migrating along the Asiatic coastline.A feedback linkage between synoptic evolution and intensification of the baroclinicity is proposed in the Greenland region for a cold low type of vortex. A cold pool, apparently created by intense radiative cooling over Greenland, was identified in early July. There was significant advective convergence associated with the thermal gradients which contributed to synoptic development as the depression migrated around this pool. It appears that the intensification of the potential temperature gradient with the advection maintained the baroclinicity, despite warm air advection into the centre of the pool. This is an interesting feature which requires further study and confirmation.

ISSN:0196-1748    

DOI:10.1002/joc.3370080203

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractMonthly rainfall data for the state of Victoria in south‐eastern Australia were analyzed using principal component analysis and Varimax orthogonal rotation, with the intention of revealing typical patterns of rainfall variability. Two data sets were used: a spatially detailed set for 1970–1980, and a less spatially detailed set for 1905–1980. The first five rotated principal component patterns (RPCPs) produced from the two data sets showed the same structure. These five RPCPs each dominated rainfall over a particular sub‐region of the study region, and the climatic regionalization that this suggested appeared to be one strongly determined by topography.The anomalies of Australian region mean monthly mean sea‐level (MSL) pressure associated with these five RPCPs of rainfall were determined using correlational techniques. Of the five main RPCPs of rainfall, the pattern based in the south‐west of the state showed the strongest relationship with monthly pressure anomalies, and was associated with the occurrence of onshore westerly winds. The results for the rainfall pattern based in northern Victoria were perhaps the most interesting. Rainfall in this region was related to the occurrence of anomalous northerly winds through southeastern Australia, although through the cooler months of the year these winds accompanied a low pressure anomaly centred over central Australia, whereas in the warmer months they were associated with a high pressure anomaly centred to the south‐east of the continent. This northern rainfall pattern also showed some month to month persistence, and a distinct correlation with the Souther

ISSN:0196-1748    

DOI:10.1002/joc.3370080204

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractA study of precipitation variations over the western Mediterranean is given, for a period of 95 years (1891 to 1985), based on the use of Principal Component Analysis. The curves for the scores are traced and then analyzed for annual as well as seasonal precipitation. Two principal moist periods are found (1901 to 1921 and 1930 to 1941) and two principal dry periods (1922 to 1929 and 1942 to 1954). A comparison of variations in precipitation and zonal indices (ZIa) indicates that with a meridional circulation dominating over the western Mediterranean, we have an increase in precipitation; with a zonal circulation dominating we have a decrease in precipitation.

ISSN:0196-1748    

DOI:10.1002/joc.3370080205

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe influence of general hemispheric circulation on European temperature and precipitation was investigated. Data from the period 1901–1976 were utilized: the monthly frequencies of occurrence of W, E, C circulation pattern types according to the Wangenheim‐Girs classification, monthly values of pressure differences between 35° an 65°N (zonal index), mean temperatures of January and July at 30 stations in both the warm season (May‐October) and the cold season (November‐April) and semi‐annual precipitation totals for 21 stations in Europe. The correlation coefficients between the circulation characteristics and climate elements indicated above in Europe were calculated.Maps of these correlation coefficients have been produced, with the areas of their statistical significance. The results show that variability of temperature, and also partly of precipitation in Europe are significantly correlated with changes of circulation pattern types. January temperature also depends on the zonal index.If it is assumed that in future, until the end of this century, an increase of W type frequency and a decrease of C circulation pattern types will take place—it may be expected that temperature and precipitation will undergo appropriate changes in certain parts of Europe. Northern and some central areas of Europe are likely to change from continental to oceanic climate as regards temperature; precipitation is likely to increase in no

ISSN:0196-1748    

DOI:10.1002/joc.3370080206

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractLocal scale ablation and energy budget measurements are reported for the Ivory glacier in the Southern Alps of New Zealand over 53 days during two consecutive summer periods. Ablation averaged 38 mm day−1, but varied from less than 10 mm day−1to over 70 mm day−1. Radiation supplied 52% of the energy for glacier melt, with the convective fluxes contributing most of the remainder. The results are related to large scale synoptic weather patterns over the southwest Pacific region. Different synoptic situations generate distinctive energy budgets, with radiation important during southerly circulation patterns and the convective fluxes relatively more important with northerly circulation patterns. These findings are discussed in the context of the retreat of New Zealand glaciers this century and possible circulation ch

ISSN:0196-1748    

DOI:10.1002/joc.3370080207

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370080208

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370080209

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370080210

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0196-1748    

DOI:10.1002/joc.3370080212

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY