东北地区典型农区土地利用变化对农业扩张和气候变化的响应研究

大规模的农业扩张和全球气候变化导致东北地区发生剧烈的土地利用/土地覆盖变化。本研究分析了研究区1976—2008年的土地利用变化和生长季各月气温的变化趋势,并结合农业扩张程度,探究LUCC对农业扩张和气候变化的响应,为指导农业发展规划和保障国家粮食安全提供理论依据。结果表明,1976—2008年农田面积逐步增加,生长季气温一直呈上升趋势。1976—2001年生长季气温的上升趋势不稳定,气温变化程度较大;2001—2008年,农业扩张放缓,生长季气温上升趋势显著,且上升趋势一直增加,气温变化比上一时期更稳定;且这两个时期农业扩张和气候变化对土地利用强度的影响在南北和东西方向上均存在明显差异。     

西宁市近三十多年来大气能见度变化特征分析

利用青海省西宁站1981年1月—2016年12月间各月地面能见度等资料,对比分析了该站大气能见度的日、季节及年际变化特征,并指出了两种不同观测方法之间的差异。分析表明:人工观测较仪器观测值平均高近66%;人工观测和仪器观测值日变化曲线基本一致,均表现为单峰单谷型,即为明显的正弦波型日变化特征;人工观测和仪器观测各月能见度均值同样均表现为单峰单谷型,夏初前后为全年高值时段,12月前后为全年低值时段;西宁近三十多年来能见度总体呈下降的趋势,有明显的高低值段区分;当出现天气现象特别是霾、雾、浮尘、扬沙、尘卷风、沙尘暴、雨、雪等时会降低大气的能见度;能见度受相对湿度的影响是显而易见的,两者呈明显的负相关。     

长江、黄河上游汛期多雨时段变化的初步分析

利用具有代表性的两个气象站汛期降水资料进行初步分析得出，黄河上游各月多雨时段出现的旬序数均有提前的趋势，尤其7月份更加明显；通天河流域各月多雨时段出现的旬序数8月变化不明显，6月偏后、7月提前。     

利用财税手段治理雾霾污染

【案情】2008年11月30日早晨,江淮、江南和西南地区东部出现很多轻雾和霾天气,其中四川东部、重庆南部、湖北西部、贵州、云南南部有能见度小于1000米的大雾。上午8点,重庆市的能见度只有100米,四川巴中300米、达州100米、南充100米、遂宁200米、湖北恩施连续两天出现能见度只有100米的大雾天气。2013年1月,我国中东部地区发生的持续大规模雾霾污     

秦皇岛市商业低碳化研究

2001—2010年秦皇岛市商业行业碳排放量分析结果显示，秦皇岛商业行业碳排放不论从总量还是排放强度均呈现增加趋势。通过剖析商业低碳化的制约因素，对秦皇岛市商业低碳化发展提出了相关建议：商业企业应积极进行内部治理，控制商业建筑的碳排放并合理选择供应商；发挥政府的主导作用，为低碳商业的发展提供良好的外部环境；合理规划商业产业与商业网点布局，积极引导、促进商业领域低碳技术的使用和发展；建立低碳商业发展专项资金，为中小型商业企业提供资金支持；加强对低碳消费的引导力度。     

成都双流机场低能见度发生规律初探

双流机场全年近1／3的日子有低见度天气出现,最多的冬季平均日数达到的总数的80％,而且低能见度有明显的季节变化和日变化。低能见度主要由辐射雾造成。二次低能见度天气为其特点,主是由弱冷空气进入暖湿气团所致。     

渤海西部局地大雾变化趋势及成因分析

利用2002-2012年秦皇岛地区4个气象站大雾监测及Micaps 3.0常规资料,对比分析卢龙与沿海站大雾的时空尺度分布特征,对大雾持续时间、日数进行跨月、跨年统计,从中筛选出189个样本个例进行变化趋势分析。对典型17个过程个例按能见度大小进行3级设定,对应其同步天气背景,分析大雾偏多的成因。     

成都地区特定灰霾天气过程与成因分析

针对2012年8月26～30日成都地区出现的灰霾天气,对当时的气象条件和污染物之间的联系进行了分析。结果表明：此次灰霾天气是由两次小的污染过程组合而成的,一次是26日、27日因气象原因和常规的内源性污染造成的,另一次是28—30日因中元节祭祖烧纸而造成的。     

四川盆地大气层结变化及其对雾霾天气影响的个例研究

四川盆地是全国人口最集中且周边地势起伏最大的区域之一,以石化燃料为主要能源,排放量较大,是我国4大雾霾高发地之一,研究四川盆地大气层结对雾霾天气的影响十分重要。利用中国气象科学数据共享网提供的高空探测资料,分析1980~2012年成都地区大气层结的分布和变化特征研究结果表明,成都地区近30年平均大气层结特征总体表现为:年平均温度随高度呈""型变化,表现为先减小后增大的变化特征。温度在地面时最大,在100h Pa附近最小;年平均温度露点差总体呈上升的变化趋势,在925h Pa以下近地面夜间平均温度露点差远高于白天;年平均风速在近地面最小约为3.5m/s,同时随高度逐渐增加。在200h Pa附近达到最大值,随后逐渐减小。在50h Pa高度以上高空风速维持在10m/s左右。在2005年12月的雾霾天气个例中,四川盆地东部连续4天出现了重度雾霾,各日14时能见度均低于2km,日较差不高于5℃,在对此次雾霾天气发生过程的观测中发现在700h Pa附近有逆温层的出现,同时在雾霾发展中期500h Pa~700h Pa间相对湿度较大;在2013年1月7日~16日的雾霾天气个例中,发现在500h Pa~700h Pa之间存在有明显扰动逆温,700h Pa以下相对湿度较大。总的来说,四川盆地雾霾天气常发生在冬季,在雾霾天气发生前期具有大气层结偏稳定,相对湿度较大,风速较小,近地面易出现逆温层等特征;在雾霾天气发生中期,逆温层的强度明显增强,相对湿度增大;雾霾天气后期,随着风速增加或降雨等大气层结的不稳定变化,雾霾天气过程结束。     

1960~2019年静海高温天气变化特征分析及日高温概率模型

利用静海国家气象站1960~2019年日最高气温资料对静海高温天气发生的开始和结束时间、次数进行了统计,分析了持续高温天气过程的年际变化规律、时间演变特征,利用Mann-Kendall法对高温日数、年最高气温进行趋势检验;构建了日高温发生概率的“钟形”曲线模型,利用傅里叶变换分析日高温发生概率序列的主要分量,构建了基于傅里叶级数的日高温发生概率简化模型。结果表明:1960年至1996年静海年高温日数呈下降趋势,1997年开始年高温日数呈上升趋势,而年最高气温无显著的上升趋势;静海高温天气过程主要为持续1~2天的过程,近20年高温热浪发生次数明显增加;近60年高温日开始时间提前,结束时间推迟的趋势明显;模型较好的模拟了日高温发生概率的变化特征。     

成都市郊区雾水中阴离子变化的研究

本文用冷凝法采集雾水样品,用离子色谱法测定雾水样品中阴离子(氟离子、氯离子、亚硝酸根离子、硝酸根离子、硫酸根离子)的浓度,研究表明雾水中阴离子浓度与雾的浓密有关,雾水中硫酸根离子含量最高;雾水中阴离子浓度随大雾的消失而降低;雾水中阴离子浓度大于雨水。所得结果对在大雾天气情况下保护人体健康有一定参考意义。     

Models of total and presumed wildlife sources of fecal coliform bacteria in coastal ponds

Models that accurately predict fecal coliform bacteria (FCB) concentrations, one of the most widely used measures of estuarine water quality, are needed to improve land use decision-making. Rapidly occurring changes in coastal land uses and the influence on water quality increases the urgency of having improved decision tools. For this study, samples were collected monthly from six coastal ponds, two tidal creeks and four shallow water wells for up to 212 years. These data were used along with other measures of environmental conditions and land classes within each watershed to construct quantitative relationships between combinations of variables and both total and presumed wildlife sources of FCB. Linear regression, bootstrapping and generalized additive modeling that incorporates both linear and nonlinear terms were used. Results of repeated simultaneous sampling on the same tide stage of ponds and downstream estuarine creeks suggest that most FCB come from wildlife and that the ponds effectively remove these bacteria except immediately following heavy rainfall. Predictive models for concentrations of total and presumed wildlife bacteria are provided along with simple measures to estimate watershed boundaries. It is proposed that these tools can be used to minimize impacts on receiving water body quality. The models can be used to test alternative development approaches within coastal watersheds similar to that found in the southeastern USA coastal zone as well as to evaluate specific proposed landscape alterations.     

WATER QUALITY CHARACTERISTICS OF STORM WATER FROM MAJOR LAND USES IN SOUTH FLORIDA1

ABSTRACT: Starting in 1998, a study was conducted to characterize storm water quality from predominant land use types in a coastal watershed along the south central coast of Florida, namely citrus, pasture, urban, natural wetland, row crop, dairy, and golf courses. Sixty‐three sampling sites were located at strategic points on drainage conveyances for each of seven specific land use areas. Runoff samples were collected following storm events that met defined rainfall criteria for a period of 30 months. Nitrogen (N), phosphorus (P), heavy metals, pesticides, and other water quality parameters were determined, and the results were analyzed to compare and characterize land uses as relative sources for these constituents in runoff. Results showed that runoff from most land use types had low dissolved oxygen concentration and that sediment and nutrient concentrations were closely related to land use, particularly to the amount of fertilizer applied in each land use. Among the eight heavy metals tested, copper was the most frequently detected and was mostly associated with runoff from citrus and golf course land uses. High levels of arsenic were also detected in golf course runoff. The most frequently detected pesticide was simazine from citrus. The information and methodologies presented may facilitate pollution source characterization and ecological restoration efforts.     

Fog collection's role in water planning for developing countries

In certain locations, the combination of meteorological conditions and topography are such that persistent fogs cover coastal or interior mountains. The droplets from these fogs are collected by trees or other tall vegetation. They can also be collected by appropriately designed man-made collectors, to provide large volumes of water for domestic, agriculture or forestry uses. The largest project to date has provided, since March 1992, an average of 11 000 litres of water per day (*****l/d) to a village of 330 people in the arid coastal desert of northern Chile. This project and others are reviewed. The impact of the deforestation of high elevation areas, and the subsequent loss of fog water input in a watershed are discussed, as are guidelines for water planners.     

HEAVY RAINSTORMS IN CHICAGO: INCREASING FREQUENCY,ALTERED IMPACTS,AND FUTURE IMPLICATIONS1

ABSTRACT: Operations of a dense raingage network in the Chicago area since 1989 provided data to assess the temporal and spatial distributions of heavy rainstorms. The 12‐year average was 4.4 storms per year, 40 percent more than in the 1948 to 1980 period, reflecting an ongoing Midwestern increase in heavy rains. The total rainfall from the 53 heavy rainstorms maximized over the city, reflecting previous observations that the influence of the city and Lake Michigan on the atmosphere causes an increase in heavy rains. Impacts from the record high number of eight storms in 2001 revealed that efforts to control flooding including the Deep Tunnel system, had reduced street and basement flooding in the moderate intensity storms, but the two most intense storms, each with 100‐year rainfall values, led to excessive flooding and a need to release flood waters into Lake Michigan. Results suggest continuing increases in the number of heavy rainstorms in future years, which has major implications for water managers in Chicago and elsewhere.     

FOG DRIP IN THE BULL RUN MUNICIPAL WATERSHED,OREGON1

ABSTRACT: Net precipitation under old growth Douglas fir forest in the Bull Run Municipal Watershed (Portland, Oregon) totaled 1739 mm during a 4Cbweek period, 387 mm more than in adjacent clearcut areas. Expressing data on a full water year basis and adjusting gross precipitation for losses due to rainfall interception suggest fog drip could have added 882 mm (35 in) of water to total precipitation during a year when precipitation measured 2160 mm in a rain gage in a nearby clearing. Standard rain gages installed in open areas where fog is common may be collecting up to 30 percent less precipitation than would be collected in the forest. Long term forest management (Le., timber harvest) in the watershed could reduce annual water yield and, more importantly, summer stream flow by reducing fog drip.     

Review of submarine groundwater discharge (SGD) in coastal zones of the Southeast and Gulf Coast regions of the United States with management implications

Groundwater serves as the primary drinking water source for over half of the coastal populations of the Southeast and Gulf Coast regions, two of the fastest growing regions in the United States. Increased demand for this resource has exceeded sustainable yields in many areas and induced saltwater intrusion of coastal aquifers. A process associated with coastal groundwater, submarine groundwater discharge (SGD), has been documented as a source of subsurface fluids to coastal ocean environments throughout the Southeast and Gulf Coast regions and is potentially a significant contributor to nearshore water and geochemical budgets (i.e., nutrients, carbon, trace metals) in many coastal regions. The importance of groundwater as a drinking water source for coastal populations and the influences of submarine groundwater discharge to the coastal ocean warrant increased research and management of this resource. This paper highlights findings from recent SGD studies on three hydrogeologically different continental margins (Onslow Bay, NC, southern Florida, and the Louisiana margin), provides background on the common methods of assessing SGD, and suggests a regional management plan for coastal groundwater resources. Suggested strategies call for assessments of SGD in areas of potentially significant discharge, development of new monitoring networks, and the incorporation of a regional coastal groundwater resources council.     

秦皇岛雷暴天气的时空尺度分布与雷电灾害分析

利用2003-2012年3～10月秦皇岛地区5个气象站雷暴监测和雷电灾害资料,采用数理统计、天气综合分析方法,得出秦皇岛地区雷暴天气的时空尺度分布特征为：全区年雷暴发生频次总体上呈递减趋势,其中,2005年35次,2008年33次,2012年20次;6月份为全年雷暴发生的峰值时段,7月、8月次之,且与秦皇岛本地主汛期相吻合;在海岸带地区由于受海洋条件影响,个别年份雷暴最早出现在2月份,最晚出现在11月中旬;雷暴天气的日时段主要出现在下午至傍晚,占70%,夜间占20%,其他时段为10%;北部山区的雷电频次大于沿海地区,对应电力、化工等行业雷电灾害呈下降趋势,但是通讯、计算机、家电等弱电系统雷击事件呈递增趋势。     

Effects of Groundwater-Flow Paths On Nitrate Concentrations Across Two Riparian Forest Corridors1

Speiran, Gary K., 2010. Effects of Groundwater-Flow Paths on Nitrate Concentrations Across Two Riparian Forest Corridors. Journal of the American Water Resources Association (JAWRA) 46(2):246-260. DOI: 10.1111/j.1752-1688.2010.00427.x Abstract: Groundwater levels, apparent age, and chemistry from field sites and groundwater-flow modeling of hypothetical aquifers collectively indicate that groundwater-flow paths contribute to differences in nitrate concentrations across riparian corridors. At sites in Virginia (one coastal and one Piedmont), lowland forested wetlands separate upland fields from nearby surface waters (an estuary and a stream). At the coastal site, nitrate concentrations near the water table decreased from more than 10 mg/l beneath fields to 2 mg/l beneath a riparian forest buffer because recharge through the buffer forced water with concentrations greater than 5 mg/l to flow deeper beneath the buffer. Diurnal changes in groundwater levels up to 0.25 meters at the coastal site reflect flow from the water table into unsaturated soil where roots remove water and nitrate dissolved in it. Decreases in aquifer thickness caused by declines in the water table and decreases in horizontal hydraulic gradients from the uplands to the wetlands indicate that more than 95% of the groundwater discharged to the wetlands. Such discharge through organic soil can reduce nitrate concentrations by denitrification. Model simulations are consistent with field results, showing downward flow approaching toe slopes and surface waters to which groundwater discharges. These effects show the importance of buffer placement over use of fixed-width, streamside buffers to control nitrate concentrations.