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Noah Wolfson

Abstract

Cloud droplet size distributions in the radius range from 0.1 to 15 µm have been investigated by remote sensing techniques. It was found that there is a large proportion of small droplets with radii <4 µm. The evolution of droplet size distribution in cold front clouds has been observed.

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Noah Wolfson
,
Judith Erez
, and
Zvi Alperson

Abstract

A real-time quality control for surface observations has been developed and tested in the Israel Meteorological Service. Error sources specific to real-time work have been defined and special procedures to deal with them were developed. A great emphasis was given to data correction so that the scheme is not confined just to the rejection of incorrect data. The criteria for the correction and rejection procedures are mostly empirical and rely much on operational experience. Accumulated statistics indicate that many reports transferred through the Global Telecommunication System are very liable to contain errors, thus emphasizing again the need for a quality control program. Future development routes are suggested.

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Joachim H. Joseph
and
Noah Wolfson

Abstract

Representative average values of the absorption to backscatter ratio of the aerosols in two typical synoptic conditions, namely cloudless khamsinic days and normal cloudless days, have been deduced from four years of data at two sites in Israel, one in the coastal plain and one in the Judean hills.

These values (15 for cloudless days and 11 for khamsinic days) have been compared to those, available in, or deducible from, published studies of the aerosol effects in various parts of the world.

It was found that the presence in the atmosphere of most of the aerosols induces a net heating effect, as far as the solar radiation balance is affected, over the regions in which they were measured.

We have further evaluated the complex part of the refractive index, averaged over the solar spectrum between 0.3 and 2.5 μm (0.03 ± 0.02 for khamsinic days and 0.08 ± 0.02 for normal days). This result is important because of the little data available for this parameter so far.

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Noah Wolfson
,
Albert Thomasell
,
Arnold Gruber
, and
George Ohring

Abstract

The impact of satellite sounding data on the systematic errors of the numerical weather prediction model of the Israel Meteorological Service has been investigated. In general, satellite data have been shown to reduce systematic error, and in particular, the greatest impact is near where the data have been introduced in the vicinity of low pressure systems.

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