ISSN:0035-9009    

DOI:10.1002/qj.49705523201

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523202

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523203

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523204

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523205

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523206

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523207

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523208

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

摘要:

AbstractWe have given an equation in which the effect of changing pressure distribution, the curvature of the path of air, and acceleration of the air, are shown separately. Reasons are put forward showing that in certain cases the effect of the changing pressure is larger than the other two terms mentioned, so that an estimate of the deviation of the wind from the geostrophic wind can be derived from an isallobaric chart. This chart should, strictly speaking, be based on instantaneous changes of pressure. The occurrence of rain in isallobaric lows, and of fine weather in isallobaric highs, is attributed to the effects of convergence or divergence over these regions of the deviations from geostrophic wind. Similar arguments hold for rainfall at fronts. Examples arc given supporting these views, and showing also that the motion of the front itself may differ from the motion computed from consideration of geostrophic wind alone. Both direct measurements of the changes of pressure, and also deductions from rates of rainfall and the movements of the fronts, indicate that deviations from gradient winds at the 600‐metre level ranging up to 5 m/s. are quite common while in extreme cases the figure may be appreciably greater. It is shown that a convergence of 5 m/s. over a circle of radius 200 km. will give rain of about 4 mm. per hour, which would be classed as heavy rain. In Appendix I. we give a computation of the effect of friction in producing rain, showing that friction can in general produce only light rain, or at most a narrow band of heavier rain, along a cold front, with very light rain behind it. In Appendix II. we show that the effect of turbulence in a smoothed sloping surface of discontinuity is to cause convergence in the lower layer

ISSN:0035-9009    

DOI:10.1002/qj.49705523209

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49705523211

出版商:John Wiley&Sons, Ltd    

年代:1929

数据来源: WILEY