Agroclimatic study of mountainous regions and its progress in China

In recent years, the agroclimatic investigations have been made at various temporal and spatial scales in moun-tainous and hilly regions, and so have the adaptability tests on the crop ecoclimate. A large quantity of reliable and representative data are obtained. Through the synthetic studies on “bell”, “layer”, “topography” and “ecological-type” in mountainy and hilly regions, climate with agriculture and zonality with non-zonality are closely combined to show the similarities and differences of agroclimatic resources at various layers and with different topography types in mountainy and hilly regions. A general review is given in this paper.     

A NUMERICAL MODEL FOR HILLY-LAND GLOBAL RADIATION

Based on the simulations of the hilly-land topographic parameters,i.e.,average orientation and slope,and topographic screen angle,a theoretical model is detailed to greater extent for global radiation overhilly countries in terms of the experimental data.Three main aspects are examined:the model construction;numerical run with the model parameters;discussion of simulations obtained locally in the model run for thesouthern Dabie Mountains.Results show that the significant effect of the topography on global radiation.The present model applies inprinciple to the numerical simulation of global radiation for any form of topography of various regions.     

海南岛农业气候区划

本文依据农业气候适宜度进行海南岛农业气候区划,其方法是应用模糊数学扩展原理建立农业气候模型,得出各地可表示农业气候资源优劣的资源指数、表示它们之间配合程度的效能指数和表示可供挖掘的资源潜力的效能利用率;以它们为区划因子,通过模糊聚类分析和模糊相似优先比进行划区。全岛分为六个农业气候区。      

甘肃省作物生态气候适生种植区与农业气候资源综合利用区划研究综述

在分析冬春小麦、秋粮、经济、瓜果、特种作物生态气候条件的基础上,将１７ 种作物进行生态气候适生种植区的划分,并提出提高气候资源利用途径。从农业气候资源、自然生态条件、农业生产特点等方面进行综合分析,将全省划分为１２ 个农业气候资源综合利用区并进行了评述。     

Climate Change and Rice Yields in Diverse Agro-Environments of India. II. Effect of Uncertainties in Scenarios and Crop Models on Impact Assessment

Estimates of impact of climate change on crop production could be biased depending upon the uncertainties in climate change scenarios, region of study, crop models used for impact assessment and the level of management. This study reports the results of a study where the impact of various climate change scenarios has been assessed on grain yields of irrigated rice with two popular crop simulation models- Ceres-Rice and ORYZA1N at different levels of N management. The results showed that the direct effect of climate change on rice crops in different agroclimatic regions in India would always be positive irrespective of the various uncertainties. Rice yields increased between 1.0 and 16.8% in pessimistic scenarios of climate change depending upon the level of management and model used. These increases were between 3.5 and 33.8% in optimistic scenarios. At current as well as improved level of management, southern and western parts of India which currently have relatively lower temperatures compared to northern and eastern regions, are likely to show greater sensitivity in rice yields under climate change. The response to climate change is small at low N management compared to optimal management. The magnitude of this impact can be biased upto 32% depending on the uncertainty in climate change scenario, level of management and crop model used. These conclusions are highly dependent on the specific thresholds of phenology and photosynthesis to change in temperature used in the models. Caution is needed in using the impact assessment results made with the average simulated grain yields and mean changes in climatic parameters.     

METHODS CALCULATING THE SPATIAL DISTRIBUTION OF AGROCLIMATIC RESOURCES IN MOUNTAINOUS AREAS AND CLIMATIC EFFECTS OF MICROTOPOGRAPHY*

The methods calculating the spatial distribution of agroclimatic resources (temperature,humidity,precipitation,wind speed,etc.) in mountainous areas are presented.The linear model can be used for the mean temperature,accumulated temperature,and the occurrence date and duration of limiting temperature,but the nonlinear model for extreme temperature,humidity,precipitation and wind speed.The climatic effects of topography obtained from the application of these methods in the Shaxi River basin,Fujian Province,are also described.The results show that the methods proposed in this paper may effectively disclose the macro-and micro-variations of spatial distribution of agroclimatic resources in mountainous areas.     

Expected changes in agroclimatic conditions in Central Europe

During the past few decades, the basic assumption of agroclimatic zoning, i.e., that agroclimatic conditions remain relatively stable, has been shattered by ongoing climate change. The first aim of this study was to develop a tool that would allow for effective analysis of various agroclimatic indicators and their dynamics under climate change conditions for a particular region. The results of this effort were summarized in the AgriClim software package, which provides users with a wide range of parameters essential for the evaluation of climate-related stress factors in agricultural crop production. The software was then tested over an area of 114,000 km² in Central Europe. We have found that by 2020, the combination of increased air temperature and changes in the amount and distribution of precipitation will lead to a prolonged growing season and significant shifts in the agroclimatic zones in Central Europe; in particular, the areas that are currently most productive will be reduced and replaced by warmer but drier conditions in the same time the higher elevations will most likely experience improvement in their agroclimatic conditions. This positive effect might be short-lived, as by 2050, even these areas might experience much drier conditions than observed currently. Both the rate and the scale of the shift are amazing as by 2020 (assuming upper range of the climate change projections) only 20?C38% of agriculture land in the evaluated region will remain in the same agroclimatic and by 2050 it might be less than 2%. On the other hand farmers will be able to take advantage of an earlier start to the growing season, at least in the lowland areas, as the proportion of days suitable for sowing increases. As all of these changes might occur within less than four decades, these issues could pose serious adaptation challenges for farmers and governmental policies. The presented results also suggest that the rate of change might be so rapid that the concept of static agroclimatic zoning itself might lose relevance due to perpetual change.     

江南丘陵和云贵高原地形对一次西南涡暴雨影响的数值试验

运用MM5数值模式对1998年7月22~23日一次由西南涡引发形成湖南大暴雨的个例进行了数值试验。模式中设计了全地形、去掉江南丘陵地形、去掉江南丘陵和云贵高原地形三种方案。对比试验表明:在去掉江南丘陵和云贵高原后,由于地形的狭管作用消失,南北热力差异减弱,低空急流随之减弱;由于低空急流对西南涡和切变线的正涡度平流输送减弱,以及500 hPa高空槽引导切变线向南移与西南涡结合,造成西南涡增强,切变线减弱、消失。同时,本文还对三种模拟试验中地形作阶梯化处理,进一步验证江南丘陵、云贵高原对偏南风存在狭管作用,对低空急流的形成有促进作用。     

华东沿海地形对登陆热带气旋运动影响的理想数值研究

利用中尺度数值模式设计一组高分辨率理想试验,采用位涡趋势方法定量诊断分析热带气旋在登陆我国华东沿海地形时,其运动发生的精细化变化以及不同因子的贡献。结果表明,平地的存在使得登陆热带气旋移速相对更快,当华东沿海地形存在时,热带气旋移速显著增大,这种增速现象主要是由于平地和地形所引起的非对称气流以及相应的引导气流变化所致,这很可能是导致预报路径误差的一个重要原因。平地试验中,陆地在热带气旋低层激发出中小尺度的非对称气流,与之不同的是,实际地形的加入激发出更大尺度并且更强的非对称偏南气流。位涡趋势方法的诊断结果表明,非引导效应总体而言对热带气旋运动贡献较小,这是因为这些因子相互抵消,但在不同的垂直层次上,不同的非引导因子贡献存在明显的差异。     

On the problem of adequate agroclimatic support of the Russian economy under climate change conditions

Problems of adapting available methods, forms, and approaches to agroclimatic support of the economy under climate change conditions are under consideration. Development and operation of an automated reference-information system (ARIS) of agricultural resources, assessment of the environmental bioclimatic potential, and preparation of agroclimatic Atlases (with a reference to hazardous agroclimatic events) are dealt with. The process of adaptation includes development of such system of agroclimatic support of the economy, which would adequately reflect the actual state of agroclimatic resources, bioclimatic potential of the environment, hazardous agroclimatic events, etc., at any prescribed moment, at any point. The problem is supposed to be solved with a mechanism of agricultural monitoring as one of the methods of agroclimatic support of the economy.