从气候振动的某些准周期看天体引潮力对天气气候的影响

本文指出,实际資料分析所揭示的气候振动准37年和准2年等周期可以从月亮相对于地球、太阳运行的准周期规律性来解释。作为这种观点的应用,文中选择了某些参数来表示月亮运行轨道的特点,并由此给出了长江中下游汛期降水量和赤道附近高空23公里附近东西风方向转换日期的超长期预报方法.結果与实际基本符合。     

湖陆风的个例分析

本文讨论了我国深水湖泊——罗加湖的湖陆风。该湖四周为群山环抱,有利于地方性风系的发展。根据1980年7月至1981年2月沿湖四周4个测站的地面风速、风向、气温、水温和小球测风等资料,本文提出了揭示湖陆(山谷)风特征的方法,着重分析了湖区风情包括涡度场和散度场的日变化,也涉及与风场相联系的温度场的变化。计算表明,湖面上有明显的日平均正涡度(8.2×10~(-5)/s)和微弱的水平散度。湖陆风发展可削弱雨季湖面降水过程。湖陆风及其反环流中心分别位于300—500m和1000m高空。其转折过程通常在1小时左右完成。     

洪泽湖水质的时空相关性分析

时空相关性分析方法在生态环境空间分异笥以及湖泊湿地自然保护区建设等方面的研究上,具有重要的应用价值。将湖泊水质监测数据与空间数据结合,建立了具有时空特征的洪渗湖水质数据库。基于相关系数矩阵,利用GIS和Origin等分析软件,对洪泽湖水质的时空相关性及其时间和空间分布规律进行了研究。结果表明,洪泽湖水质存在着时空相关性,目前这种时空相关性已受到人类活动的强烈干扰,因此,建议洪泽湖湿地自然保护区应该选择在时空间相关性小,具有一定离群性的“岛屿”区域。     

秋冬季环境下固定化氮循环细菌净化湖泊水体氮污染动态模拟

本文依据太湖秋冬季水体氮污染的特点,应用辐射增殖氮循环细胞进行了净化湖水氮污染的动态模拟实验,研究结果表明,富营养化湖水经固定化氮循环净化后,总氮下降７２．４％,氨氮下降８５．６％,出水水质得到明显改善,固定化氮循环细茵在冬季低温（７℃）条件下仍保持了较高的降氮能力,总氮和氨氮去除率分别为５５．６％,５８．９％,降氮效果与湖水滞留时间有关,探讨了固定化氮循环细茵的降氮机理。     

太湖：过去、现在和将来

The presence of roads, farm house foundations, wells and Liangzhu period cultural relics in the bottom of Lake Taihu attest to the fact that this shallow depression was probably dry between 4 and 5 thousand years ago. This interpretation is corroborated by the sudden disappearance of algal pigments at sediment depths carbon-14 dated at 4-5 thousand years before present.In winter, the stronger winds are predominantly from the northeast. These winds result in a powerful counterclockwise current that transports lake sediments and has altered the very shape of the lake over the last 300 years. Winds produce a complex mixing pattern in Lake Taihu with storm induced sediment deposition occurring near the lake''s center.During approximately 240 days of the year, the wind blows across Lake Taihu with sufficient force to mix it to its bottom. As a result, this polymictic lake rarely becomes anoxic and dissolved oxygen at the mud water interface is maintained at or above 4 mg·l^-1. The consequences of this high dissolved oxygen are quite impressive as high organic loading to the lake would otherwise render its bottom waters anaerobic killing many of its natural inhabitants.Because suspended solids reduce (attenuate) light penetration, the major primary production takes place in the top metre of the lake (mean Secchi Transparency-0.25 m). Suspended clays are slow to settle and wind mixing keeps fine-grained suspended solids in suspension in all but the most quiet backwaters of the lake.In the recent past about 23 000 metric tonnes of phytoplankton were produced in Lake Taihu. This large production represents only about 5% of the total influx of organic material entering the lake. In summer and fall, cyanobacteria such as Microcystis spp. and Anabaena spp. dominate most of the lake. Recently, however, mixotrophic flagellates displaced cyanobacteria as the dominant algae in parts of Lake Taihu with high bacteria and high suspended solids (e.g. Wuli and Meiliang Bay). In the future, facultative heterotrophs may come to dominate an ever larger portion of the lake waterc column.     

用生态修复调控浮游植物种群局部控制富营养化——以贵州红枫湖水质生态修复工程为例

利用物理生态工程在水深10 m左右,水位变幅7 m左右的贵阳红枫湖/水库(正常水位时57.2 km2)右二湾富营养水体进行局部(围隔水体面积1.33 hm2)生态修复.对工程前后和内外水体浮游植物的群落结构、丰度、生物量等进行比较,结果表明,当植物浮岛覆盖率超过1/5～1/3时(可视为阈值),物理生态工程可以调控浮游植物种群结构和丰度,浮游植物优势种群由生态修复前的微囊藻属、角甲藻属及同期外环境的蓝藻门蓝纤维藻属转变为硅藻门的直链藻属.工程内与工程外比较,种属数减少了29.4%,特别是减少了蓝藻中可能释放藻毒素的微囊藻、鱼腥藻等属,蓝藻丰度和生物量分别减少了55.5%和57.9%;而硅藻的种属数则增多120.0%,且其丰度和生物量分别增加了56.4%和60.3%.从藻类总体统计资料看,工程内与工程外比较,藻类丰度减少53.6%,生物量减少39.1%,透明度提高了数十厘米以上,稳定在120～220 cm.当工程区外浮游植物优势种群是蓝藻,暴发蓝藻水华,且可释放藻毒素的种属有多次检出时,工程区内仍然以硅藻为优势种,未曾检测出可释放藻毒素的种属,从而在红枫湖局部水体实现了水质改善和富营养化控制.在目前高污染负荷下恢复浅水湖泊沉水植被时,本项目发展的可全年镶嵌式种植包括香根草、杞柳等高杆植物在内的多种水面植物的浮岛可作为防浪削浪、遏制蓝藻、改善水质、提高透明度的先锋性措施,以保障局部水面植被覆盖面积超过上述阈值,成为保护沉水植物生长、遏制暴发蓝藻水华的可操作途径.     

中国太湖物理—生物工程实验中菱对水质影响的模式

A model on a physico-biological engineering experiment for purifying water in Wulihu Bay of Lake Taihu by using Trapa natans var. bispinosa was constructed. The state variables in water in the physico-biological engineering were ammonium nitrogen (NH₄⁺-N); nitrate nitrogen (NO₃^--N); nitrite nitrogen (NO₂^--N); phosphate phosphorus (PO₄^3--P); dissolved oxygen (DO); nitrogen (N) and phosphorus (P) in detritus; biomass density, N and P in phytoplankton and in Trapa natans var. bispinosa, N and P in the substance adsorbed by the membrane of the engineering and the rootstocks of Trapa natans var. bispinosa. The state variables in bottom mud layer were PO₄^3--P in the core water,exchangeable P and N. The external forcing functions were solar radiation, water temperature, NH₄⁺-N; NO₃^--N; NO₂^--N; PO₄^3--P; N and P in detritus; DO; phytoplankton concentrations in inflow water and the retention time of the water in physico-biological engineering channel. The main physical, chemical and biological processes considered in the model were:growth of Trapa natans var. bispinosa and phytoplankton; oxidation of NH₄⁺-N and NO₂^--N, of detritus break down; N and P sorption by the enclosure cloth of the experimental engineering and by the rootstocks of Trapa natans var. bispinosa in water; reaeration of water; uptake of P, NH₄⁺-N, NO₃^--N by phytoplankton and Trapa natans var. bispinosa:mortality of the phytoplankton and Trapa natans var. bispinosa:settling of detritus; and nutrient release from sediment. Comparison of calculated results and observed results showed that the model was constructed reasonably for the experiment. The mechanism of purifying lake water in the experiment engineering was discussed by the use of the model.     

太湖水动力学三维数值试验研究─1.风生流和风涌增减水的三维数值模拟

本文建立了太湖风生流和风涌增减水的一个三维数值模型,该模型可对垂直方向进行多层次划分,且各计算网格点层数一样。模拟计算了１９９７年８月的１１号台风对太湖水位和湖流作用,用环湖六个水位站水位过程资料对模型计算出的水位进行了验证,并用太湖梅梁湖湾口的实测流速资料对模型计算出流场进行了校验。     

日本琵琶湖的水动力三维数值模拟

在笛卡尔坐标下，运用流体水动力学的方法，并在前人观测资料的基础上建立了一个三维水动力数值模式，并对日本琵琶湖风生流进行了数值模拟。结果表明，在５ｍ／ｓ的东南风、西南风、东北风作用下，湖的北端均有气旋式环流出现，在５ｍ／ｓ西北风作用下，湖的北端有反气旋式环流出现。在各种方向风速驱动下，中、低层场或形成与表层一致的环流型，或呈现明显的垂直切变。     

大气近地面层中不同温度层结下的湍流运动

本文运用相似理论,在物理分析的基础上试图从统一的观点来讨论不同温度层结下的湍流运动。由强迫对流到自由对流的过渡趋势假定是连续的,对极端稳定层结时湍流运动的特点提出了看法。选取了符合物理分析所要求的通用函数的形式,设法确定了其中的参数的值,并进而建立了根据梯度观测资料计算湍流系数及各种湍流输送通量的公式及图表,并用不同资料进行了检验。