Some remarks on cumulus parameterization

A simple parameterization of cumulonimbus convective heating is presented. The model is primarily based on preserving a moisture budget and on detraining cloud air at levels corresponding to the neutral buoyancy of the air converged at low levels. Results are compared with data from the western Pacific and GATE. Agreement is good. Suggestions are offered for improving the model and extending it to other regions.     

Emission of nitric oxide from soils and termite nests in a Trachypogon savanna of the Orinoco basin

Nitric oxide fluxes from soils in the Trachypogon savanna of the Orinoco basin were determined during the dry season using the static chamber method. The emission from dry soils fluctuated from 0.4 to 3 ng N m^–2 s^–1 and increased up to 25 ng N m^–2 s^–1 after moderate watering or light rain-falls (1 to 5 mm). The mean emission values are up to 6 times lower than one observed earlier at the Chaguaramas site, but up to 10 times higher than one recorded at the Guri site, indicating an important spatial variability in NO fluxes of the Venezuelan savanna region. The changes observed after the addition of nitrogen to the soil, in the form of ammonium and/or nitrate, indicate a high denitrification potential in this acidic soil. Burning of the surface vegetation produced an increase by a factor of 10 in the emission rate of NO, but the effect was relatively short in time, about 5 days. It was estimated for the savanna region that burning increases the total NO soil emission during the dry season by 15% compared to the unburnt case. Soils with termite nests emit 10 times more NO than soil without nests, but the contribution from this source is less than 2% of the total savanna soil flux.     

9216号热带风暴的初步分析

对9216号热带风暴在9月1日02时中心分裂的原因,作了初步探讨,认为东南低空急流使热带风暴倒槽区的气旋性环流加强,以及低涡的吸引合并,是产生新中心的原因。青岛产生大暴雨的条件,是充沛的水汽,强烈的上升运动和长波槽东移影响。     

东亚和西太平洋爆发性温带气旋发生的气候学研究

本文利用历史天气图资料,对1973—1988年中国东部和沿海地区的温带气旋及其爆发性发展情况进行了统计,共有1014个温带气旋发生,其中有1/5达到了爆发性发展的强度,构成了西太平洋爆发性海洋气旋的一部分.它占整个西太平洋爆发性气旋总频数(包括不同来源)的51％.进而对这类爆发性气旋的活动规律进行了分析,概括出了它们的气候学特征.比较亚洲大陆、中国近海及西太平洋地区的爆发性温带气旋表明,西太平洋地区不仅频繁而且强烈.而东、西太平洋地区发生海洋爆发性气旋的对比表明,二者存在着明显的差异.同时也指出,东太平洋地区爆发性气旋的发生并不是一种少见的现象.     

NUMERICAL EXPERIMENT OF THE INFLUENCES OF HEAT AND WIND STRESS ON THE EQUATORIAL OCEAN CIRCULATION*

A time-dependent linear model on the equatorial beta plane is developed in this paper.Its vertical structure consists of two active layers with equal density and temperature above the thermocline and a quasi-stationary layer with constant density below the thermocline.The results of nurnericat experiments show that the direct influence of heat on the equatorial ocean is much smaller than that of wind stress.Nevertheless,through the tropical ocean-atmosphere interaction,the change of wind stress resulting from the thermal forcing may set a determinant effect on the equilibrium and anomalous development of the ocean-almosphere circulation.     

NUMERICAL EXPERIMENT OF THE INFLUENCES OF HEAT AND WIND STRESS ON THE EQUATORIAL OCEAN CIRCULATION

A time-dependent linear model on the equatorial beta plane is developed in this paper.Its verticalstructure consists of two active layers with equal density and temperature above the thermocline and aquasi-stationary layer with constant density below the thermocline.The results of nurnericat experiments show that the direct influence of heat on the equatorial ocean ismuch smaller than that of wind stress.Nevertheless,through the tropical ocean-atmosphere interaction,the change of wind stress resulting from the thermal forcing may set a determinant effect on the equilibriumand anomalous development of the ocean-almosphere circulation.     

TROPICAL ATMOSPHERIC NONLINEAR STEADY RESPONSE SOLUTION UNDER EFFECTS OF PAIRED HEAT SOURCES OF CONTRASTING NATURE

Based on steady semi-geostrophic model equations,analysis is carried out of the linear and nonlinearmodification/response of the tropical atmosphere to the forcing of ideal paired heat sources of contrasting nature.Re-suits show that the linear part is dominant in the steady response but the nonlinear modification is quite noticable in theneighborhood of the heat source and between the paired sources,and the barotropic mode and second baroclinic modeplay a different role in the modification,with the barotropic(second baroclinic)mode modification depending largely onthe Rossby wave self-interaction(the magnitude due to the Kelvin-Rossby wave interaction)between the pairedsources.     

计算机天气图图形识别

根据天气系统的定义和实际业务中的天气图分析规范，总结出了５００、７００、８５０ｈＰａ３层高空天气图上特征等高线，特征等温线，槽线（含切变线），高（低）中心，冷（暖）中心以及热带气旋的识别方法及其判别式，并给出了实现计算机自动识别的程序设计步骤。