The radiative forcing benefits of “cool roof” construction in California: quantifying the climate impacts of building albedo modification

Exploiting surface albedo change has been proposed as a form of geoengineering to reduce the heating effect of anthropogenic increases in greenhouse gases (GHGs). Recent modeling experiments have projected significant negative radiative forcing from large-scale implementation of albedo reduction technologies (“cool” roofs and pavements). This paper complements such model studies with measurement-based calculations of the direct radiation balance impacts of replacement of conventional roofing with “cool” roof materials in California. This analysis uses, as a case study, the required changes to commercial buildings embodied in California’s building energy efficiency regulations, representing a total of 4300 ha of roof area distributed over 16 climate zones. The estimated statewide mean radiative forcing per 0.01 increase in albedo (here labeled RF01) is ?1.38 W/m². The resulting unit-roof-area mean annual radiative forcing impact of this regulation is ?44.2 W/m². This forcing is computed to counteract the positive radiative forcing of ambient atmospheric CO₂ at a rate of about 41 kg for each square meter of roof. Aggregated over the 4300 ha of cool roof estimated built in the first decade after adoption of the State regulation, this is comparable to removing about 1.76 million metric tons (MMT) of CO₂ from the atmosphere. The point radiation data used in this study also provide perspective on the spatial variability of cool roof radiative forcing in California, with individual climate zone effectiveness ranging from ?37 to ?59 W/m² of roof. These “bottom-up” calculations validate the estimates reported for published “top down” modeling, highlight the large spatial diversity of the effects of albedo change within even a limited geographical area, and offer a potential methodology for regulatory agencies to account for the climate effects of “cool” roofing in addition to its well-known energy efficiency benefits.     

云南省细网格气候区划及气候代表站选取

利用1961—2008年云南省124站气温观测资料,经过地形订正后,形成1km×1km的细网格点数据。在此基础上,开展了云南省细网格气候区划及气候代表站选取的研究。结果表明,云南可划分为高原气候带、温带、北亚热带、中亚热带、南亚热带和北热带等6个气候带,所占面积分别为3.32×104、3.65×104、15.65×104、6.82×104、8.66×104和1.31×104km2;高原气候带分布在滇西北3000m以上高海拔地区,温带主要分布在滇东北和滇西北海拔高度为2200～3000m的地区,北亚热带主要分布在滇中、滇西、滇南高海拔地区和滇北低海拔地区,中亚热带主要分布在滇中、滇东南和滇西南海拔较高的地区,南亚热带主要分布在滇南和河谷地区,北热带主要分布在滇南和海拔较低的河谷地区;各气候带分布与地形和纬度相关联,地形因素比行政区域更能体现气候特征;通过站点序列与气候带序列趋势变化一致性和偏离程度的统计分析,所选气候代表站与相应气候带序列变化非常一致,能够较好地代表云南各气候带变化特征     

中国东部夏季降水型的年代际变化及其与北太平洋海温的关系

采用中国160站降水资料、NOAA ERSST海温资料以及ERA－40大气再分析资料, 分析了中国东部夏季降水型的年代际变化特征及其与北太平洋海温的可能联系。结果表明: 中国东部夏季降水型在近50年中经历了两次年代际变化, 第1次发生在20世纪70年代中后期, 北太平洋中纬度地区冬季海温由正距平向负距平转变, 太平洋年代际振荡(PDO, Pacific decadal oscillation) 由负位相向正位相转变, 通过影响东亚夏季风环流, 使东亚夏季风减弱, 中国东部夏季降水从北到南呈现出“＋－＋” 转变为“－＋－”的三极分布形态, 这次年代际变化体现了同一模态正负位相的转变; 第2次发生在20世纪80年代末90年代初, 北太平洋海温转变为日本以南西北太平洋的正距平分布, 同时菲律宾群岛附近海温偏暖, 西太平洋副热带高压偏南偏西, 使得中国东部夏季降水由北至南转变成“－＋”的偶极分布形态, 这次年代际变化体现了一种模态向另一种模态的转变。     

Agrometeorological models for forecasting the qualitative attributes of “Valência” oranges

Forecasting is the act of predicting unknown future events using available data. Estimating, in contrast, uses data to simulate an actual condition. Brazil is the world’s largest producer of oranges, and the state of São Paulo is the largest producer in Brazil. The “Valência” orange is among the most common cultivars in the state. We analyzed the influence of monthly meteorological variables during the growth cycle of Valência oranges grafted onto “Rangpur” lime rootstocks (VACR) for São Paulo, and developed monthly agrometeorological models for forecasting the qualitative attributes of VACR in mature orchard. For fruits per box for all months, the best accuracy was of 0.84 % and the minimum forecast range of 4 months. For the relation between °brix and juice acidity (RATIO) the best accuracy was of 0.69 % and the minimum forecast range of 5 months. Minimum, mean and maximum air temperatures, and relative evapotranspiration were the most important variables in the models.     

2016年梅雨持续性强降水期间大气环流稳定分量研究

梅雨降水具有显著的阶段变化特征,研究持续强降水期间的关键环流稳定分量,对于分析和预测梅雨降水具有重要意义.利用NCEP-DOE1979～2016年逐日再分析资料,对2016年梅雨持续强降水期间位势高度场、风场和相对湿度场进行分析,提取环流系统的关键稳定分量,并对其空间结构、演变特征及更长时间尺度的背景形势进行分析,为梅...     

基于多元数据的城市工业布局气候适宜性评估——以淄博为例

本文以淄博市城市发展战略规划（2017—2030年）为例,开展了基于多元数据的城市工业布局气候适宜性评估。基于气象、遥感、环保等多元资料,对城市规划密切相关的风环境、热环境、大气环境等进行了综合分析。结果表明：研究区主导风向和风速大小存在一定空间差异,北部的桓台和临淄的主导风路径多以东—西为主,其余地区以南—北路径为主,临淄的东部地区和淄川的中部地区为常年风速大值区,而周村、张店的大部分地区和博山的南部区域为风速小值区;城市热岛范围随时间扩张明显,以两轴区域为核心,呈蔓延式发展,较强以上等级热岛面积由2009年的405 km2发展至2016年的918 km2,其中张店区的增幅速度最快;敏感性模拟试验显示,易在山前出现污染汇聚带,PM2.5污染物高浓度主要分布在淄博的中北部平原地区,而市域北部和东部区域的污染扩散条件相对较好,各区域工业排放大气污染物的扩散特征主要受不同区域的主导风影响,其中淄川北部与张店南部的污染物扩散易对整个中心城区产生较大影响。综合考虑以上风环境、热环境、大气环境的分析结果,将规划区进行大气环境敏感区等级划分,明确了5类区域的工业布局气候适宜性,从改善局地气候与大气环境角度提出规划建议,为合理配置土地功能、优化工业布局提供了科学支撑。     

Projected changes in the characteristics of the East Asian summer monsoonal front and their impacts on the regional precipitation

Summer monsoonal rainfall over East Asia is dominated by precipitation associated with the East Asian summer monsoonal front (EASMF). A Community Atmospheric Model (CAM5.1) with a high horizontal resolution of 50 km is employed in this study to investigate the interannual variability as well as projected future trends in the EASMF under the Representative Concentration Pathway 8.5 scenario. Seasonal march of the EASMF is reproduced reasonably well in the model’s present-day simulation despite a northward shift of the simulated front from its observed position. Based upon a suite of objectively-defined daily indices of the EASMF, we show that the EASMF in the late twenty-first century will be more intense and displaced eastward and southward from its present-day mean location. Moreover, EASMF events will exhibit a wider meridional expansion and a longer duration. Monsoonal precipitation over East Asia is particularly sensitive to the meridional displacements of EASMF. In conjunction with the projected southward shift of EASMF, an enhanced rain band is seen to extend northeastward from southern China to the northwestern Pacific south of Japan. This precipitation feature is associated with strengthened and southward-shifted westerly jet streams at 250 and 700 hPa, which are respectively linked to tropical warming in the upper troposphere and warming over the South China Sea in the lower troposphere during the twenty-first century. Within the latitudinal “gap” south of the upper-level jet and north of the lower-level jet, the local vorticity tendencies are maintained by upper-level divergence and lower-level convergence, thus accompanied by enhanced upward motion and precipitation. The site at which this “jet stream-precipitation” relationship prevails is notably modulated by long-term trends in the temperature and circulation patterns associated with climate change.

     

West African monsoon: is the August break “breaking” in the eastern humid zone of Southern Nigeria?

In July, heating of the continents in the Northern Hemisphere results in strengthened monsoon systems which bring rains to West Africa. In Nigeria, the annual rainfall total decreases from over 3,800 mm at Forcados on the coast to under 650 mm at Maiduguri in the north-east of the country. June, July, August and September are the rainiest months throughout the country. In many parts of the south, however, there is “supposed to be” a slight break in the rains for some 2 to 3 weeks in late July and early August or the so called “August break”. In this study, we are underscoring the obvious that climate is changing. The daily series of rainfall data for 1983–2003 analyzed between the months of July–August for some sites in the Eastern humid zone of Southern Nigeria shows that the “August break” may indeed “be breaking”. We have discussed some practical approaches to climate change research in this monsoon region.     

Spatial impact of projected changes in rainfall and temperature on wheat yields in Australia

Climate projections over the next two to four decades indicate that most of Australia’s wheat-belt is likely to become warmer and drier. Here we used a shire scale, dynamic stress-index model that accounts for the impacts of rainfall and temperature on wheat yield, and a range of climate change projections from global circulation models to spatially estimate yield changes assuming no adaptation and no CO₂ fertilisation effects. We modelled five scenarios, a baseline climate (climatology, 1901–2007), and two emission scenarios (“low” and “high” CO₂) for two time horizons, namely 2020 and 2050. The potential benefits from CO₂ fertilisation were analysed separately using a point level functional simulation model. Irrespective of the emissions scenario, the 2020 projection showed negligible changes in the modelled yield relative to baseline climate, both using the shire or functional point scale models. For the 2050-high emissions scenario, changes in modelled yield relative to the baseline ranged from ?5 % to +6 % across most of Western Australia, parts of Victoria and southern New South Wales, and from ?5 to ?30 % in northern NSW, Queensland and the drier environments of Victoria, South Australia and in-land Western Australia. Taking into account CO₂ fertilisation effects across a North–south transect through eastern Australia cancelled most of the yield reductions associated with increased temperatures and reduced rainfall by 2020, and attenuated the expected yield reductions by 2050.     

江西省早稻雨洗花灾害时空变化及分区

雨洗花灾害是江西省早稻的主要农业气象灾害之一。基于1981-2017年江西省早稻种植区81个气象站逐日降水量资料和14个水稻观测站发育期和产量资料,利用旋转经验正交函数分解（REOF）等方法,探讨江西省早稻雨洗花灾害的时空变化和分区特征并得到典型场。结果表明:江西省早稻雨洗花灾害发生频率总体呈东北高、西南低,赣北南部高、两侧低的分布特征,高值区位于萍乡北部、宜春南部、新余、南昌、抚州北部至赣东北地区,发生频率在60%以上,低值区位于赣州和吉安西南部,发生频率低于40%。轻度雨洗花灾害持续影响江西省大部分地区,且自1992年以来呈现发生频率增加、影响范围扩大的趋势;重度灾害主要发生在赣东北,经历了两个活跃期和两个低发期。根据REOF分析结果,可将江西省早稻雨洗花灾害划分为赣北南部、赣中、赣东北、赣南和赣北北部5个区域。赣东北为重度雨洗花灾害高风险区,赣北南部为轻度雨洗花灾害高风险区,赣中、赣北北部为轻度雨洗花灾害次高风险区,赣南为雨洗花灾害低风险区。     

东亚阻高与我国夏季暴雨

本文对1966—1989年6—8月亚洲东部中高纬(45—75°N,80—120°E)阻塞高压活动进行了研究。指出,在这种环流背景下,我国东部地区常出现大范围连续暴雨天气。还利用500hPa东亚(100—120°E)地转风场,探讨了我国主要暴雨带与东亚阻高南侧东风、南支西风急流、中纬北风南界以及低纬最大南风轴之间的相互关系。     

贵州“2011.6”两次暴雨数值模拟研究

应用湿位涡理论,利用贵州84个县市地面气象观测站及1473个乡镇自动站逐时降水观测资料、ECMWF提供的0.25°×0.25°再分析格点资料及非静力中尺度模式WRF提供的数值模拟结果,对贵州省2011年6月17日08:00~18日20:00(简称“过程Ⅰ”)和6月22日08:00~23日20:00(简称“过程Ⅱ”)两次典型暴雨过程的θ_se和湿位涡进行诊断分析和数值模拟。结果表明:“过程Ⅰ”受一股冷空气影响,“过程Ⅱ”受两股冷空气影响。“过程Ⅰ”辐合中心位于27°N、107°E上空800hPa处,辐散中心位于27°N、107°E上空550hPa处。“过程Ⅱ”辐合中心位于27°N、107°E上空800hPa处,辐散中心位于28°N、107°E上空750hPa处。“过程Ⅰ”,贵州上空700hPa至近地面的MPV1正值中心和MPV2负值中心的分布与大暴雨落区(兴仁-晴隆-安顺和金沙-湄潭-务川)基本一致,“过程Ⅱ”MPV1的两个正值中心和MPV2强负值中心与大暴雨落区(毕节、六枝)吻合。两次暴雨天气过程中的贵州上空MPV1值明显比MPV2值偏大。WRF模式模拟的水汽辐合中心强度比实况偏强,模拟的“过程Ⅰ”辐合区比实况偏小,模拟的“过程Ⅱ”辐合区比实况偏大。WRF模式模拟“过程Ⅰ”的贵州上空MPV1正值区中心值比实况偏小,模拟“过程Ⅱ”的贵州上空MPV1正值区中心值比实况偏大,但模拟的正值中心与强降水中心基本一致。WRF模式对两次暴雨过程MPV2负值中心的模拟均表现为不太准确。WRF模式模拟影响贵州的冷空气比实况偏强,模拟的特大暴雨中心值比实况偏大,但“过程Ⅰ”模拟的特大暴雨中心位置比实况偏南10km,“过程Ⅱ”模拟的特大暴雨中心位置比实况偏南7km,可供贵州β中尺度暴雨预报参考。      

北半球极涡指数对高原夏季降水的影响

利用奇异值分解方法(SVD)分析了夏季降水对极涡面积和极涡强度指数的响应,研究发现,冬季北半球极涡指数场与高原夏季降水场,在青海省大部分是明显的负相关区域,西藏大部分以正相关为主;春季北半球极涡指数场与西藏和青海夏季降水场为正相关。冬季12月极涡指数与高原夏季6月降水的相关,自高原东南部到西北部呈“+-+”分布;冬季1月极涡指数与高原夏季7月降水相关,南北呈“+-”分布,西藏为正相关,青海为负相关;冬季2月极涡指数与高原夏季8月降水,除柴达木盆地北侧、西藏西部为弱的负相关外,其余地区均为正相关。      

中国东北地区冬季气温变化特征及其大气环流异常的关系

利用1957-2010年冬季中国东北地区90站气温资料,应用REOF和聚类分析方法将东北划分为南、北两个冬季气温变化子区,分析讨论其冬季气温的变化趋势和冷暖异常特征,及其与主要环流指数之间的同期和滞后关系。使用向后去除变量选择法,选取最优预测因子,并建立了全区和各子区的回归统计模型。结果表明：东北冬季增温较明显,平均上升速率达到0. 45 ℃/ 10 a,北部略高;与同期欧亚纬向环流指数之间存在着较显著相关;前期8月东太平洋副热带高压面积指数、前期10月亚洲区极涡面积指数和前期8月北半球极涡面积指数与东北冬季气温存在着显著相关,复相关系数达到0.70,并且是回归方程最关键预测因子。在对冷、暖冬预测时,可以把选定时段和区域副热带高压和极涡面积指数作为重要的影响因素,且误报率较低。     

GIS-based high-resolution spatial interpolation of precipitation in mountain–plain areas of Upper Pakistan for regional climate change impact studies

In this study, the baseline period (1960–1990) precipitation simulation of regional climate model PRECIS is evaluated and downscaled on a monthly basis for northwestern Himalayan mountains and upper Indus plains of Pakistan. Different interpolation models in GIS environment are used to generate fine scale (250?×?250 m²) precipitation surfaces from PRECIS precipitation data. Results show that the multivariate extension model of ordinary kriging that uses elevation as secondary data is the best model especially for monsoon months. Model results are further compared with observations from 25 meteorological stations in the study area. Modeled data show overall good correlation with observations confirming the ability of PRECIS to capture major precipitation features in the region. Results for low and erratic precipitation months, September and October, are however showing poor correlation with observations. During monsoon months (June, July, August) precipitation pattern is different from the rest of the months. It increases from south to north, but during monsoon maximum precipitation is in the southern regions of the Himalayas, and extreme northern areas receive very less precipitation. Modeled precipitation toward the end of the twenty-first century under A2 and B2 scenarios show overall decrease during winter and increase in spring and monsoon in the study area. Spatially, both scenarios show similar pattern but with varying magnitude. In monsoon, the Himalayan southern regions will have more precipitation, whereas northern areas and southern plains will face decrease in precipitation. Western and south western areas will suffer from less precipitation throughout the year except peak monsoon months. T test results also show that changes in monthly precipitation over the study area are significant except for July, August, and December. Result of this study provide reliable basis for further climate change impact studies on various resources.     

Conditions for freezing precipitation at some airports of Russia and the CIS: IV. Airport of Nizhni Novgorod

Results of study of conditions for freezing precipitation (FP) at the airport of Nizhni Novgorod based on 20-year series of surface observations are described. The cloud tops are estimated from radiosonde data. It is found that the monthly mean FP frequency does not exceed 0.44%; the phenomenon occurs from October to February. Over 20 years, a total of 113 FP episodes were observed, or less than six episodes annually. Freezing precipitation is more frequent at night and in the morning and very rare in the afternoon, at surface air temperatures not exceeding 0°C and not below ?10°C; in half of the cases, the air temperature is within ?0.1 to ?2.0°C. Surface wind is most frequently from south or southwest, while in the lower 4-km layer, according to the radiosonde data, wind direction mostly veers with height from south to west and north. In the boundary layer, FP is often associated with low-level jet streams, most frequently of southwest direction in the cloudy layers. The warm layers within and below the clouds occur in more than 20% of the cases. The most typical precipitation is FP from “all cold” clouds. Using objective criteria of the fronts, synoptic situations, advection, and baroclinicity, it is shown that almost all cases of freezing rain are observed in frontal zones, while freezing drizzle is as frequent at the fronts as under airmass conditions. Both types of FP are associated mainly with high baroclinicity and warm advection. The results can be used to develop an objective method of FP forecasting.     

两系法杂交稻65396在我国一季稻区的制种播差期决策

以具有超高产水平的两系杂交稻 6 5 396 (培矮 6 4 s× E32 )为研究对象 ,在分析母本不育系培矮 6 4 s用作单季稻区域制种时的稳定不育期的季节和持续期的基础上 ,用生育期模型分析了培矮 6 4 s与 E32在南方一季稻区制种时的播差期及其变化规律。研究得到的两系法杂交稻制种技术的气象学方法可供其他熟制地区应用。     

1966—2015年天山南北坡空气湿度差异及其影响因素

利用天山地区近50年(1966—2015年)逐日气象资料,采用Mann-Kendall趋势检验法研究了天山南北坡相对湿度(RH)的时空变化特征,分析了天山南北坡RH对平均气温、降水量、平均风速、参考蒸散量、日照时数的敏感性,并探讨了引起RH变化的主导因素。结果表明：(1)整个天山地区RH变化有略微上升的趋势但不显著,北坡RH总体呈下降趋势,南坡RH总体呈上升趋势。(2) RH空间分布呈自北向南递减趋势,南北坡全年及春季以下降趋势为主,而夏、秋、冬三季均以上升趋势为主,且南坡变化趋势的显著性高于北坡。(3) RH对风速、气温、日照时数及参考蒸散量均为负敏感,对降水量为正敏感。北坡RH对各气象因子的敏感程度依次为日照时数>参考蒸散量>风速>气温>降水量,南坡敏感程度依次为日照时数>风速>参考蒸散量>气温>降水量。空间分布上,仅降水量敏感系数高值区位于北坡伊犁河谷,其余要素敏感系数高值区均位于南坡。(4)参考蒸散量是影响天山地区RH变化的主导因子,整个天山地区参考蒸散发贡献率较高,日照时数贡献率高值区集中于北坡伊犁河谷,风速、降水量、气温贡献率高值区均集中于南坡克孜勒苏地区。     

基于气候适宜度的南方柑橘种植精细化气候区划

为探究气候变化对南方柑橘种植气候适宜性的影响,基于气候适宜度函数建立柑橘发育期温度、降水、日照以及综合适宜度模型,对南方柑橘种植区近60年(1960-2019年)361个气象站观测数据进行精细化插值(Anusplin插值)并计算气候适宜度,采用自然断点法分4个等级对柑橘种植区进行气候区划,并分前、后30年对比分析研究区...     

2013年云南冬季四次降雪天气过程对比分析

利用NCEP 1°×1°资料和实况观测资料,针对2013年冬季云南4次降雪过程,使用诊断和对比的方法,分析研究4次降雪过程在形成机理等方面的异同点。结果表明:4次降雪中南支槽型降雪强度和范围明显强于非南支槽型;700h Pa上高度场北高南低型和锋区密集型为主要环流形势;南支槽前的西南暖湿气流与北方冷空气的交汇,会导致降水的明显加强。在锋面附近形成的中尺度垂直环流系统,随着北方冷空气进一步南下,θ_se线陡立区的存在或移动引起南方暖湿气流带来的水汽凝结和不稳定能量的释放,从而为降雪提供了足够的抬升凝结条件,降雪或强降雨就发生在θ_se线陡立区附近以及暖湿不稳定区域;强大的地面冷高压南压和地面冷空气的参与,能够为降雪提供有利的温度条件,更有利于降雪天气的产生和维持。