三河市40年来温度和降水变化及对农业生产的影响

对三河市1960~2002年气温和降水等气象数据分析结果表明,该区气温以每年0.04℃的速度上升,且不同季节的变化亦不同,冬季增温最明显,夏季最小,春秋季居中;积温也呈增加趋势,增加趋势总积温>0℃以上年积温>10℃以上年积温。降水年季变化有一定的减少,5年时段变化20世纪60年代初至90年代末减少了150mm,且降水减少的时间主要集中在夏玉米生长季节,同时降水的变化对冬小麦的种植和生长有一定影响。     

Impact of expected increase in precipitation intensities on soil loss—results of comparative model simulations

The impact of the expected climate change on the frequency and extent of soil erosion processes is hardly assessable so far. This is mainly because available models of climate change reliably produce at best mean daily precipitation data, whereas erosion is the result of extreme but short time rainfall and runoff events, normally lasting no longer than a few hours. The frequency and intensity of these extreme rainfall events are expected to increase in some regions, which could lead to increased erosion rates. Mathematical models are able to describe erosion rates under conditions of these extreme events, however, so far prognostic meteorological data necessary for the application of these models are not available.The use of a new method for the projection of meteorological time series and their extremes using global climate simulations [Enke and Spekat, 1997, Enke, 2000, Enke, 2003, Enke et al., 2005 and Enke et al., in press] permits for the first time an approximation of future soil loss.This research is based on simulated, high resolution data for extreme rainfall events in the period of 2031–2050, which reproduces the mean frequency, intensity and duration of future events with high precipitation intensities relevant to erosion within the investigated seasonal period from June to August. The simulations are performed for two exemplary sites in Saxony, based on the EROSION 2D model (Schmidt, J., 1990. A mathematical model to simulate rainfall erosion, Catena, Suppl. 19), which is a process-based soil erosion model for simulating soil erosion and deposition by water on single slopes. Simulated precipitation for the 2031–2050 time period is used to model soil loss, and results are compared to soil loss based on 20 years of measured precipitation from 1981 to 2000.The simulation results allow the impacts of climate change on erosion rates to be quantified by comparing current climate with predicted, future climate. However, expected changes in land use due to changed economic conditions are not taken into account in this analysis.     

CO2浓度升高及降水变化对红砂植物碳氮特征的影响

本研究以荒漠优势植物红砂（Reaumuria soongorica） 1年生幼苗为研究对象,采用开顶式生长箱（Open top chambers,OTCs）模拟CO₂浓度变化（350和700 μmol·mol^-1）,研究了降水变化（-30%,-15%,0,+15%和+30%）及其协同作用对红砂地上和地下部分碳、氮含量与积累量的影响。结果发现：CO₂浓度倍增和降水对红砂地上和地下部分有机碳、全氮含量和有机碳积累量以及地上全氮积累量影响极显著,并且表现出极显著的交互作用。CO₂浓度倍增下,红砂地上和地下部分有机碳、C/N和有机碳积累量以及地下部分全氮显著增加。随着降水增加,红砂地上和地下部分有机碳含量和积累量以及地下部分全氮均呈增加趋势,地上和地下部分C/N呈先降后升趋势,而地上部分全氮先升后降。综上所述：未来CO₂升高时,降水增加协同高CO₂浓度有助于红砂植株有机碳积累,从而促进红砂植株对氮素的吸收,降水减少则有利于红砂调节自身碳氮平衡从而提高其抗旱性。     

养分添加和降水变化对荒漠草原植物群落物种多样性和生物量的影响

本研究旨在探讨荒漠草原植物群落物种多样性及生物量对养分添加和降水变化的适应策略,以期为退化荒漠草原的恢复和管理提供理论基础。本试验在宁夏荒漠草原开展了养分添加和降水变化野外控制试验,通过测定植物群落物种数及生物量,研究养分添加和降水变化对荒漠草原植物群落物种多样性和生物量的影响。结果表明：养分添加显著降低禾草丰富度（P<0.05）;减少50%降水显著降低Shannon-Wiener指数和物种总丰富度,增加50%降水显著增加物种总丰富度（20.5%～28.2%）（P<0.05）;养分添加和增加50%降水显著提高植物群落盖度和生物量（P<0.05）;减少50%降水条件下,养分添加处理与不添加处理相比植物群落地上生物量显著提高（54.3%～75.6%）（P<0.05）;植物群落地上生物量与Shannon-Wiener指数和物种总丰富度呈显著正相关（P<0.05）。研究表明：减少50%降水条件下,养分添加能够缓解水分对荒漠草原植物生长的限制,其中氮磷钾添加缓解效果优于氮添加。     

班玛县气温和降雨量对禾本科、莎草科产草量的影响

选择典型的高寒草甸为研究对象,分析1995~2004年气温和降雨量变化对禾本科和莎草科产草量的影响。结果表明,禾本科产草量与气温呈线性函数关系变化,且相关性达到显著水平,禾本科产草量与降雨量的相关性不显著;莎草科产草量与气温的相关性不显著,莎草科产草量与降雨量呈线性函数关系变化,且相关性达到显著水平。     

黑龙江省作物生长季降水年际、年代际变化的区域差别

采用REOF法对黑龙江省5～9月降水异常进行了分区,分析了不同分区内降水的变化趋势和周期性特征,结果表明,黑龙江省降水异常可分为西南部、东部和西北部3个分区;西南部旱涝事件交替频繁,西北部强的旱涝事件发生概率最小,20世纪70年代末～80年代初,西南部和西北部降水减少趋势显著,其他时段内降水无显著变化趋势,不同分区内降水变化存在阶段性特征;3个降水异常分区降水均存在不同尺度的年际、年代际变化特征,西南部降水准11年尺度的周期变化和东部三江平原2～4年尺度周期信号在整个时域中均有体现.     

影响郴州台风降水气象因子分析

为了做好郴州台风降水气候预测,对影响郴州台风降水的诸多气象因子做统计分析,结果表明,冬、夏季海温变化和西太平洋副热带高压位置是影响台风降水的重要因素,夏季暖水状态下,影响台风个数及降水总量偏少,但从冬季到夏季海温若处于上升趋势,且副高位置偏北时,影响台风个数及降水总量明显偏多;夏季冷水状态下,影响台风个数及降水总量偏多,但从冬季到夏季海温若处于下降趋势,且副高位置偏南时,影响台风个数及降水总量明显偏少。     

1983～2013年成县干旱规律统计及影响分析

对成县地区1983 ～2013年的干旱现象以及降水量进行统计,总结干旱降水的分布特点.结果表明,该地区干旱的发生频率较高,按季节划分可以发现夏季干旱发生的频率最高,其次是春季干旱;春季干旱近年来有明显的增加,冬季以及秋季干旱次数减少;降水的时间分布不均匀是导致农业干旱的主因;干旱的发生程度具有阶段性特征,且有一定的连旱现象,多是3～5年一旱;干旱对于作物的产量影响显著,凡遇旱作物均因缺水等现象发育成长不良.     

新旧型自动气象站气象数据一致性分析

利用曹县、定陶2014年1～12月新旧型两套自动气象站的气温、相对湿度、降水资料,通过对SPSS软件的使用以及数据极值的延续性分析,研究了新旧型自动气象站数据的一致.结果表明,新型自动气象站相对于旧站,其气温、相时湿度数据一致程度较好,新型站对气温变化观测的反应更加迅速;称重式雨量传感器与人工站差值百分率在4％以下,符合自动站降水质量评估参考标准.     

Responses of enzymatic activities within soil aggregates to 9-year nitrogen and water addition in a semi-arid grassland

Soil microorganisms secrete enzymes used to metabolize carbon (C), nitrogen (N), and phosphorus (P) from the organic materials typically found in soil. Because of the connection with the active microbial biomass, soil enzyme activities can be used to investigate microbial nutrient cycling including the microbial response to environmental changes, transformation rates and to address the location of the most active biomass. In a 9-year field study on global change scenarios related to increasing N inputs (ambient to 15 g N m⁻² yr⁻¹) and precipitation (ambient to 180 mm yr⁻¹), we tested the activities of soil β-glucosidase (BG), N-acetyl-glucosaminidase (NAG) and acid phosphomonoesterase (PME) for three soil aggregate classes: large macroaggregates (>2000 μm), small macroaggregates (250–2000 μm) and microaggregates (<250 μm). Results showed higher BG and PME activities in micro-vs. small macroaggregates whereas the highest NAG activity was found in the large macroaggregates. This distribution of enzyme activity suggests a higher contribution of fast-growing microorganisms in the micro-compared with the macroaggregates size fractions. The responses of BG and PME were different from NAG activity under N addition, as BG and PME decreased as much as 47.1% and 36.3%, respectively, while the NAG increased by as much as 80.8%, which could imply better adaption of fungi than bacteria to lower soil pH conditions developed under increased N. Significant increases in BG and PME activities by as much as 103.4 and 75.4%, respectively, were found under water addition. Lower ratio of BG:NAG and higher NAG:PME underlined enhanced microbial N limitation relative to both C and P, suggesting the repression of microbial activity and the accompanied decline in their ability to compete for N with plants and/or the accelerated proliferation of soil fungi under elevated N inputs. We conclude that changes in microbial activities under increased N input and greater water availability in arid- and semi-arid grassland ecosystems where NPP is co-limited by N and water may result in substantial redistribution of microbial activity in different-sized soil particles. This shift will influence the stability of SOM in the soil aggregates and the nutrient limitation of soil biota.