Anoxia over the western continental shelf of India: bacterial indications of intrinsic nitrification feeding denitrification

Studies on the Arabian Sea coastal anoxia have been of immense interest, but despite its ecological significance there is sparse understanding of the microbes involved. Hence, observations were carried out off Goa (15 degrees 30'N, 72 degrees 40'E to 15 degrees 30'N, 72 degrees 59'E) to understand the processes that mediate the changes in various inorganic nitrogen species in the water column during anoxia. Water column chemistry showed a clear distinct oxic environment in the month of April and anoxic condition in October. Our study based on microbial signatures indicated that oxygen deficit appeared as a well-defined nucleus almost 40 km away from the coast during the oxic period (April) and spreads there after to the entire water column synchronizing with the water chemistry. Striking results of net changes in inorganic nitrogen species in nitrification blocked and unblocked experimental systems show that denitrification is the predominant process in the water column consuming available nitrate ( approximately 0.5 microM) to near zero levels within approximately 72 h of incubation. These observations have been supported by concomitant increase in nitrite concentration ( approximately 4 microM). Similar studies on denitrification-blocked incubations, demonstrate the potential of nitrification to feed denitrification. Nitrification could contribute almost 4.5 microM to the total nitrate pool. It was found that the relation between ammonium and total dissolved inorganic nitrogen (DIN) pool (r=0.98, p<0.001, n=122) was significant compared to the latter with nitrite and nitrate. The occurrence of high ammonium under low phosphate conditions corroborates our observations that ammonium does not appear to be locked under low oxygen regimes. It is suggested that ammonium actively produced by detrital breakdown (ammonification) is efficiently consumed through nitrification process. The three processes in concert viz. ammonification, nitrification and denitrification appear to operate in more temporal and spatial proximity than hitherto appreciated in these systems and this gives additional cues on the absence of measurable nitrate at surface waters, which was earlier attributed only to efficient algal uptake. Hence we hypothesize that the alarming nitrous oxide input into the atmosphere could be due to high productivity driven tighter nitrification-denitrification coupling, rather than denitrification driven by extraneous nitrate.     

积云并合降水数值模拟

用积云二维时变模式模拟长沙夏秋季积云并合过程，结果表明：系统性天气积云从生，常产生自然并合，降水量很大；有些可播度大于零的天，积云散在发生，几天自然并合，降水量少，若在附近有一扰动产生积云，并合将使其发展强盛，降水量增加；可播度为零的天气，即使积云相距很近也不合并，而是先后消散，无作业价值。     

1994—1996年湖南连续三年洪涝的环流形势对比分析

在概述了１９９４－１９９６年湖南连续三年洪涝基础上，着重分析了形成这种洪涝的５００ｈＰａ环流形势，并且进行了对比分析，指出湖南汛期产生持续性暴雨的必要条件是要有稳定的环流形势和冷暖空气的交绥，而阻塞高压的存在是环流形势稳定的重要标志之一；我国西部高原的西部有切断低压存在则是冷暖空气在湖南上空交绥的重要标志。     

下击暴流实例分析

通过实地灾情调查,本文提供了一个证据较为充分、说服力较强的下击暴流实例,加深了人们对下击暴流的感性认识。实践证明,在观测密度(时间和空间上)远不能满足中小尺度分析要求、探测手段受到很大限制的情况下,用实地灾情调查和地面拍照的办法进行下击暴流这类中小尺度系统的分析是可行的。     

试论气象预报员的素质

指出了天气气候预报是气象部门的主体工作,论述了预报员的素质问题,即个体素质和整体素质。个体素质主要指预报员的业务技能、敬业钻研精神、高尚的职业道德、一丝不苟、脚踏实地的工作作风和良好的心理素质等。整体素质主要指预报集体的协作精神、学术民主、注重天气会商和维护集体荣誉等。     

Political unification and regional consequences of German East-West migration

"The purpose of this paper is to evaluate the impact of the post-unification East to West transfer of the German population on levels of spatial concentration and deconcentration in Eastern and Western Germany. Using 1991 internal migration data, it was found that German East-to-West migration served to deconcentrate regional population in the West, but concentrate population in the East. Regional variations in German East-to-West migration during 1991 can be explained by the availability of employment and housing, a distance-minimisation effect, and the location of relatives and friends."     

双候西风场中期降水客观预报方法

作者在亚洲自然天气区域的基础上,提出可用一条特征等高线来表征中纬度西风场特征的观点,进而提出一种双候相似相关的中期降水客观预报方法.经1988—1989年两年使用结果表明.它可以提高中期降水预报的能力.     

论湿积温

作者在积温概念的基础上提出了湿积温的新概念,并指出:积温、当量积温只是湿积温的一种特例,从而把积温、当量积温有机地统一于湿积温概念之下。本文论证了湿积温的如下优越性: 1.植物生长发育与温度的关系从积温概念下的线性关系变为湿积温概念下的非线性关系; 2.植物生长发育不仅与温度有关,而且还与湿度有关; 3.对同一地区、同一植物而言,湿积温是个相对稳定的常量; 4.T>Tc时,湿积温便得到有效抑制。 因而,它有重大的理论意义和广阔的应用前景。