فاعلية مؤشرات عدم الاستقرار الجوي الرياضية المعمول بها في وسط المملكة العربية السعودية

الملخص EN

Atmospheric stability is very important for man and his activity.

Therefore, many Atmospheric Stability Indices have been developed by meteorologists to understand the atmospheric stability.

These indices have been developed to go well with the climatological and geographical situations in the countries in which they have been developed.

However, recently these indices are used in many places to forecast the atmospheric stability including Saudi Arabia.

Hence, this study comes to examine the ability of these indices in detecting and forecasting the stability condition in the middle part of Saudi Arabia.

To achieve this goal/many meteorological programs and statistical packages were employed, including the United State Air force (USAF) meteorological program Rawinsound Observation (RAOB).

The data used in this research varies with respect to their sort and its spatial and temporal coverage.

It represents daily surface and upper data for many metrological variables for Riyadh station and extends form 1994 to 1998.

The Riyadh station has been chosen to represents the middle part of Saudi Arabia because it locates in the center of studied region.

The study has revealed many important results.

It has been found that there are values and constants in the mathematical structure of the studied indices that are not in coherence with the climatologicall and geographical setting of the middle part of Saudi Arabia.

Also, it has been found that some of these indices fail in detecting and forecasting the instability in the region.

This failure varies between these indices; the worst among these indices are LI and SWI indices.

The less failure are TTI and KI indices, nevertheless, they still, in some times, fail in detecting and forecasting the instability condition in the region.

Finally, it have been found that the performance of these indices during the spring season is better then during the winter season, however, they fail sometimes in detecting and forecasting the instability in the region in the that season.