57年来本溪冷凉山区温度降水变化对蒸发的影响

利用草河口1953～2009年月平均气温、降水量、小型蒸发资料,采用线性倾向率、Mann-Kendall(简称M-K)方法对蒸发量进行了趋势分析和突变检测。结果表明,冷凉山区年蒸发量呈现波动性增加趋势,其线性倾向率为30.16 mm/10a;四季的蒸发量均呈增加趋势;年蒸发量随着温度升高呈增加趋势,随着降水增加而呈减少趋势;蒸发最大值出现在5月份,最小值出现在1月份。     

土壤蒸发,蒸散模型的研究

本文根据陆地蒸发的机理和过程，提出下垫面蒸发的相似性的理论，并将陆地蒸发分为非限制蒸发和限制蒸发两种类型。然后利用器测法收集的数据资料，建立了土壤蒸发、蒸散的数学模型，为进一步研究土壤水分消退规律和蒸发力的计算提供了依据。     

Estimation of evaporation rate from the forest floor using oxygen-18 and deuterium compositions of throughfall and stream water during a non-storm runoff period

Rainwater, throughfall, stream water during a non-storm runoff period, and soil water were sampled about every 10 days at six nested basins within the Hitachi Ohta Experimental Watershed in Japan from 1998 to 2001. Basins HA and HB are covered with an 80-year-old artificial forest of Japanese cypress and Japanese cedar. HC and HV are covered with 12-year-old forest of the same species. HO and HX are covered with various aged stands of the same species. The samples were analyzed for the isotopic compositions of ¹⁸O and deuterium (D). The weighted means of ¹⁸O (D) in HA and HB were –7.35 (–46.7) and –7.38 (–46.8), while they were –7.51 (–48.1) and –7.57 (n/a) in HC and HV, respectively. They were –7.50 (–47.6) and –7.41 (–47.1) in HO and HX, respectively. There was a relative difference of 0.2 (1.4) in ¹⁸O (D) between 80-year-old and 12-year-old forest. The stream water during a non-storm runoff period is considered to reflect the effect of evaporation from the forest floor. The evaporation rates from the forest floor were estimated using values in throughfall and stream water using the Rayleigh distillation equation under equilibrium conditions. They were estimated to be 5.5 (9.1), 5.2 (9.0), and 4.9 (8.7)% of annual throughfall in HA, HB, and HX (mature forests), respectively, using ¹⁸O (D), and 4.0 (7.6), 4.1 (8.1), and 3.5 (n/a)% of annual throughfall in HC, HO, and HV (young forests), respectively.     

Evapotranspiration components and dual crop coefficients of coffee trees during crop production

Quantifying crop water consumption is essential for many applications in agriculture, such as crop zoning, yield forecast and irrigation management. The objective of this study was to determine evaporation (E), transpiration (T) and dual crop coefficients (Ke and Kcb) of coffee trees during crop production (3rd and 4th year of cultivation), conducted under sprinkler and drip irrigation and no irrigation, in Londrina, Paraná State, Brazil. Crop evapotranspiration (ET) was measured by weighing lysimeters cultivated with plants of cultivar IAPAR 59, E was measured by microlysimeters installed on the lysimeters and T was obtained by the difference between ET and E. The crop coefficient (Kc) was determined for the irrigated treatments as the ratio between ET and the reference evapotranspiration (ETo). Similarly, evaporation coefficient (Ke) and basal crop coefficient (Kcb) were determined as the ratio of E and T, respectively, to the value of ETo, which was estimated by the ASCE Penman-Monteith method on an hourly basis. The values of E and Ke varied due to atmospheric demand and water application method. Those factors, in addition to crop phenology and leaf area evolution, also influenced T and Kcb. Regardless irrigation treatment, the measured values of E represented 35% of ET, while T was 65% of ET. The recommended values of Ke were 0.46 and 0.26 for sprinkler and drip irrigation, respectively. The recommended values of Kcb were 0.52 and 0.82 for sprinkler-irrigated, and 0.5 and 0.65 for drip-irrigated treatments, varying as a function of daily ETo (ETo ≥ or <3 mm day⁻¹, respectively).     

沧州市近 40 年蒸发量变化特征分析简

利用沧州市气象站1971～2010年期间小型蒸发皿（口径20cm）蒸发量资料,对近40年沧州市蒸发量变化进行统计分析。结果表明,近40年沧州蒸发量变化较大,在年内呈波状分布,蒸发量最大的为6月,最小的为1月;近加年小型蒸发皿蒸发量呈总体下降趋势,蒸发量最大为2273．3min,出现在1972年,最小为1681．4mm,出现在1990年,年最大蒸发量与最小蒸发量相差591．9mm;近40年一年四季中夏季蒸发量最大,变化幅度也最大,春季次之,冬季蒸发量及变化幅度最小;不同季节蒸发量变化趋势不同,蒸发量下降主要在春季和秋季,夏季无明显变化,而冬季蒸发量呈上升趋势;沧州近40年蒸发量年代际变化呈波状变化,整体下降趋势;年代特征明显,20世纪80年代为各年代最高值,平均蒸发量为1958．6mm,高出近40年平均值39．7mm,21世纪以来蒸发量为1880．9mm,为各年代最低值,比平均值低38．0mm。     

蒸发条件下土壤水盐热运移的实验研究

土壤水盐热的耦合运移研究是土壤水盐运移理论研究的重要组成部分.在模拟蒸发条件下,通过室内土柱实验,对土壤水盐热的迁移做了初步研究.结果表明:地下水位的高低直接影响土壤剖面盐分和水分分布;本实验一直处于稳定蒸发状态,今后需进一步研究不同蒸发条件下土壤水盐热的运移规律.     

主要森林植被土壤及枯落物水分蒸发量动态研究

运用固定标准地观测的方法,对辽东山区几种主要森林植被落叶松幼龄林、落叶松中龄林、红松幼龄林、红松中龄林、柞树林、杂木林土壤的枯落物水分蒸发量进行测量。试验表明单位面积上落叶松幼龄林的平均日蒸发量最小,农田的日蒸发量较大。影响单位面积蒸发量的主要因子为地表枯落物量,同时蒸发量又与郁闭度呈弱负相关,地表至20 cm表层土壤的水分蒸发量占总蒸发量的绝大部分,而20 cm以下的土壤失水很少,红松林的土壤水分在20 cm以上的土层有上下交流的现象,而农田的水分上下交流活跃带可深达25 cm。根据布兰尼—尼里德尔公式推算出了辽宁省实验林场邻域范围内的年土壤和枯落物水分蒸发量,表明蒸发量的月份间差异显著,蒸发量冬季较小而在夏季很大。     

秦岭西部地区近41年来气候变化特征

[目的]研究秦岭西部地区近41年来的气候变化特征。[方法]根据秦岭西部17个气象站1967~2007年间观测数据,分析了秦岭西部近41年来的气候变化特征。[结果]过去41年间,秦岭西部的平均气温增幅为0.30℃/10a(P0.000 1);四季平均气温均呈显著上升趋势,冬季增温速率最大(0.42℃/10a)。年平均月极端最高气温上升趋势显著(0.31℃/10a,P0.05),冬季平均月极端最高气温上升最快(0.54℃/10a,P0.05);年平均月极端最低气温上升趋势显著(0.36℃/10a,P0.05),夏季平均月极端最低气温上升最快(0.45℃/10a,P0.005)。41年间平均年降水量为802 mm,变化趋势不显著,但春季降水量显著下降(-13.68 mm/10a,P0.05);年日照时数和年相对湿度呈下降趋势,但变化趋势不显著,平均年日照时数为1 864 h;年蒸发量呈增加趋势,但变化趋势不显著。从地域差异上看,年平均气温、年降水量和年相对湿度都呈现由南部向北部地区递减的趋势,年日照时数和年蒸发量则呈现由南部向北部地区递增的趋势。[结论]该研究可为秦岭西部地区生态系统的稳定及相关研究提供参考依据。     

1985～2010年南京市蒸发特征分析

[目的]分析1985～2010年南京市蒸发量的变化特征。[方法]利用1985～2010年南京市E601B型蒸发器蒸发量资料,采用线性回归、趋势分析、距平分析等方法,对近26年南京市蒸发量的变化特征及其影响变化的原因进行了分析。[结果]1985～2010年南京市年、季蒸发量均存在上升趋势,其中春季蒸发量的上升趋势最为明显,其次为夏季和秋季,冬季蒸发量上升的趋势最不明显,年蒸发量的变化主要是由春夏季蒸发量的变化引起的;影响蒸发量变化的因子有气温、地面温度、日照时数、平均风速、相对湿度、气压、降水等,通过对影响因子与蒸发关系的相关分析表明,蒸发量与气温、平均风速、地面温度呈正相关,与相对湿度、降水量和气压呈负相关;其中与相对湿度、气温、气压和地面温度的相关性较好,与降水量、日照时数、风速相关性较小;蒸发是各种气象要素综合作用的效应,且蒸发量与相对湿度的相关性最好。[结论]该研究为水资源评价和气候变化分析提供理论依据。     

日光温室不同栽培茬口番茄需水量初探

作物的需水量由植株蒸腾和棵间蒸发两部分构成。试验分别研究了日光温室冬春茬和秋冬茬的植株蒸腾量和棵间蒸发量,同时也研究了植株蒸腾量和棵间蒸发量与日光温室内的光、温、湿以及水面蒸发的相关性。结果表明：番茄植株蒸腾量在秋冬茬随生育进程呈逐渐减少的趋势,最大值在开花结果期为457.92ml H2O/(d·plant),到成熟采摘时最少,为78.95ml H2O/(d·plant);冬春茬则相反,随番茄的生长发育进程植株的蒸腾逐渐增加,在营养期最低为135.78ml H2O/(d·plant),在果实膨大期最大为524.24ml H2O/(d·plant)。棵间蒸发在两个栽培茬口的趋势与植株蒸腾相似。经计算得到秋冬茬番茄的需水量为2098.95m3/hm2,冬春茬番茄的需水量为2789.25 m3/hm2。冬春茬对植株蒸腾与棵间蒸发影响最大的分别是温度和湿度;而在秋冬茬对植株蒸腾与棵间蒸发影响最大均为光强。