Impact of chilling accumulation and hydrogen cyanamide on floral organ development of sweet cherry in a warm region

The microscopic investigation of the floral development of sweet cherry（Prunus avium L. cv. Hongdeng） from a warm winter climate（Shanghai） and cold winter climate（Tai＇an, Shandong Province, China） was conducted to explore the reason of low fruit set. The effect of hydrogen cyanamide（HCN） on floral development under warm winter conditions was also investigated. Trees grown in Shanghai with insufficient chilling accumulation exhibited little difference in the progression of microspore development compared to trees in Tai＇an that accumulated adequate chilling, but showed substantial delays in ovule and embryo sac development. The growth of nucelli did not proceed beyond the macrospore mother cell and macrospore stages with abortion rates of 13, 15 and 45% by 6, 3 and 0 d before full bloom, respectively. These abnormalities in the ovule and embryo sac in the Shanghai-grown trees were eliminated by HCN application. These results suggest that chilling regulates the development of female floral organs in winter dormancy; therefore, insufficient chilling accumulation, causing abnormality of the female floral organs, restricts the cultivation of sweet cherry in warm winter regions. Interestingly, HCN application, which decreased the chilling requirements for Hongdeng, may be a potential strategy for sweet cherry cultivation in warm winter regions.

Spatial and temporal change patterns of freeze-thaw erosion in the three-river source region under the stress of climate warming

The three-river source region(TRSR), located in the Qinghai-Tibet Plateau in China, suffers from serious freeze-thaw(FT) erosion in China. Considering the unique eco-environment and the driving factors of the FT process in the TRSR, we introduce the driving force factors of FT erosion(rainfall erosivity and wind field intensity during FT period) and precipitation during the FT period(indicating the phase-changed water content). The objective was to establish an improved evaluation method of FT erosion in the TRSR. The method has good applicability in the study region with an overall precision of 92%. The spatial and temporal changes of FT erosion from 2000 to 2015 are analyzed. Results show that FT erosion is widely distributed in the TRSR, with slight and mild erosion being the most widely distributed, followed by moderate erosion. Among the three sub-regions, the source region of the Yellow River has the slightest erosion intensity, whereas the erosion intensity of the source region of Yangtze River is the most severe. A slight improvement can be observed in the condition of FTerosion over the whole study region from 2000 to 2015. Vegetation coverage is the dominant factor affecting the intensity of FT erosion in the zones with sparse vegetation or bare land, whereas the climate factors play an important role in high vegetation coverage area. Slopes>28° also have a significant effect on the intensity of FT erosion in the zones. The results can provide a scientific basis for the prevention and management of the soil FT erosion in the TRSR.

Climate transformation to warm-humid and its effect on river runoff in the source region of the Yellow River

The change characteristics and trends of the regional climate in the source region of the Yellow River, and the response of runoff to climate change, are analyzed based on observational data of air temperature, precipitation, and runoff at 10 main hydrological and weather stations in the region. Our results show that a strong signal of climate shift from warm-dry to warm-humid in the western parts of northwestern China （Xinjiang） and the western Hexi Corridor of Gansu Province occurred in the late 1980s, and a same signal of climate change occurred in the mid-2000s in the source region of the Yellow River located in the eastern part of northwestern China. This climate changeover has led to a rapid increase in rainfall and stream runoff in the latter region. In most of the years since 2004 the average annual precipitation in the source region of the Yellow River has been greater than the long-term average annual value, and after 2007 the runoff measured at all of the hydrologic sections on the main channel of the Yellow River in the source region has also consistently exceeded the long-term average annual because of rainfall increase. It is difficult to determine the prospects of future climate change until additional observations and research are conducted on the rate and temporal and spatial extents of climate change in the region. Nevertheless, we predict that the climate shift from warm-dry to warm-humid in the source region of the Yellow River is very likely to be in the decadal time scale, which means a warming and rainy climate in the source region of the Yellow River will continue in the coming decades.

Water Resources of the South Asian Region in a Warmer Atmosphere

The global mean surface temperature may rise by about 0.3t per decade during the next few decades as a result o f anthropogenic greenhouse gas emissions in the earth's atmosphere. The data generated in the greenhouse warming simulations (Business-as-Usual scenario of IPCC) with the climate models developed at Max Planck Institute for Meteorology, Hamburg have been used to assess future plausible hydrological scenario for the South Asian region.The model results indicate enhanced surface warming (2.7) for summer and 3.6℃ for winter) over the land reginos of South Asia during the next hundred years. While there is no significant change in the precipitation over most of the land regions during winter, substantial increase in precipitation is likely to occur during summer. As a result, an increase in soil moisture is likely over central india, Bangladesh and South China during summer but a statistically significant decline in soil moisture is expected over central China in winter. A moderate decrease in surface runoff may occur over large areas of central China during winter while the flood prone areas of NE--India, Bangladesh and South China are likely to have an increase ill surface runoff during summer by the end of next century.

Regional warming induced by urban surface expansion in Shanghai

To detect the impacts of urban surface expansion on surface air temperature at 2-m（SAT） in Shanghai, China, nested numerical integrations based on satellite-derived urban data between the 1980 s and 2010 s were performed using the Weather Research and Forecasting（WRF） model. Urban surface expansion induced an annual-averaged warming of 0.31 °C from 1980 to 2016 across the whole of Shanghai, showing the greatest intensity between 2010 and 2016. The values were 0.36, 0.78, and 0.75 °C over grids that were classified as urban in both time periods（U2 U）, landuse grids that changed from non-urban to urban（N2 U）, and urban areas（including U2 U and N2 U）, respectively, and revealed weak warming over the inner-ring areas because the urban surfaces had been there since the 1980 s, whereas warming areas were coincident with the outward expansion of the urban surface. Meanwhile, marked seasonal variations could be detected, which were greater in spring and summer but less in autumn and winter. The approximately homogenously distributed SAT maximum（weaker） and heterogeneously SAT minimum（stronger） contributed to the decreased diurnal temperature range. Regional warming induced by urban surface expansion was approximately 0.12 °C per decade, which accounted for 19% of the overall warming across the whole of Shanghai. The values were 0.11 °C per decade and 0.39 °C per decade over U2 U and N2 U, which accounted for approximately 17% and 42% of the overall warming, respectively, and resulted in approximately 41% of the overall warming over urban areas.

Effects of Climate Warming on Animal Husbandry in Chaoyang Region

[Objective] To study the effects of climate warming on animal husbandry in Chaoyang region and provide a scientific basis for government guidance on animal husbandry. [Method] According to the climatic data between 1952 and 2008 and animal husbandry data between 1978 and 2008 of Chaoyang region, changes in average annual temperature in winter, annual slaughter numbers of pig and sheep and total output value of animal husbandry were analyzed by least square method and Excel software. [ Result] In Chaoyang region, the average annual temperature in winter increased with years; the annual slaughter numbers of pig and sheep increased rapidly; and the total output value of animal husbandry increased largely. [ Conclusion] The climate warming maybe promotes the development of animal husbandry in Chaoyang region.

1980—2016年中国北方风蚀气候侵蚀力的变化

随着修订风蚀方程(RWEQ)的提出,采用增加了冻结因子的气候因子(WF)表达风蚀气候侵蚀力更具有科学性和必要性。基于中国北方风蚀区157个气象站1980—2016年的观测数据,逐月计算了各站点气候因子,并探讨了气候因子时空分布变化特征及影响因素。结果表明:①1980—1997年,年气候因子值表现为快速下降,从940.46 kg/m下降到273.03 kg/m;而1998—2016年,年气候因子值表现相对稳定,在139.81~398.85 kg/m范围内波动。②春季气候因子值约占全年63%,其变化也显著高于其它季节,这也是土壤风蚀发生在春季的主要原因。③气候因子的高值区分布在新疆东部、青海西部、40°N以北的内蒙古中西部,这与气压中心和高大山体地形分布有关。

耳螺在中国海的北扩:三种耳螺在我国黄海的报道(腹足纲:耳螺科)

2020~2023年,作者在我国黄海沿岸潮间带进行软体动物多样性调查时获取到多个耳螺科标本,通过形态学比较和研究,鉴定为3属3种,分别为:中国耳螺Ellobium chinense(Pfeiffer,1855)、赛氏女教士螺Pythia cecillii(R.A.Philippi,1847)和教徒肋耳螺Laemodonta exaratoides Kawabe,1992。中国耳螺和赛氏女教士螺采自江苏盐城,教徒肋耳螺采自青岛和大连。作者对这3种耳螺进行了分类学描述和报道,其中教徒肋耳螺在我国沿海系首次报道,为中国新记录种。作者基于COⅠ、16S rRNA和H3基因对教徒肋耳螺进行了系统发育分析,确定了该种在耳螺科中的分类地位。耳螺科是典型的暖水性类群,在我国主要见于热带和亚热带海域,之前仅有中国耳螺可向北扩散至黄海南部。该研究中3种耳螺在黄海的发现表明该海域内的耳螺种类在不断增多,且出现了明显的北扩现象。这种现象很可能与全球变暖导致的黄海水温持续升高有关。研究结果不仅丰富了中国海软体动物多样性研究内容,也为更好地理解气候变化背景下软体动物的扩布提供了新的数据和资料。

甘肃省暖季降水日变化特征

利用2013—2022年4—10月甘肃省340个气象站点逐1 h降水观测资料,揭示了甘肃省暖季降水在日变化尺度上的精细化演变特征,并分区域进行讨论分析,为甘肃省极端降水事件的研究提供科学参考。结果表明:(1)甘肃暖季降水量和降水强度日变化峰值主要出现在10:00—13:00,降水频率日峰值在夜间22:00—01:00居多。降水日变化季节性差异明显,中南部有较为集中的秋雨分布。(2)降水日变化区域性特征鲜明,祁连山区、甘肃中部和高原边坡的降水时段主要在白天,午间较强的降水强度主导着降水量的白天峰值;河西西部降水量和降水频率日峰值多出现在夜间,但短时较强降水在18:00—21:00有一定突发性;陇东南和陇东地区降水呈非均匀分布,在降水频率夜间峰值影响下夜雨频繁,但降水较强的时段分别在午后和早晨。(3)不同持续时间降水特征不同,持续时间在6 h及以下的短时降水,降水日变化多呈“双峰型”。持续时间在6 h以上的降水日变化近似于“单峰型”,多在傍晚开始,夜间达到峰值,于次日中午结束。

中国降水再循环率对全球变暖的响应

中国地域广阔,涵盖了多种气候类型和地形特征,这为降水再循环过程提供了复杂的环境条件,使得在研究降水再循环率特征时难以对区域进行划分和比较。本文利用优化后的降水再循环率评估模型计算中国地区降水再循环率,研究了中国地区降水再循环率的变化特征及其对全球变暖的响应。结果表明,1979—2020年,中国降水再循环率具有明显的区域和季节性差异,其中青藏高原的再循环率最高,降水再循环率的大值区和线性增长的区域主要位于非季风区的内陆湿润地区;但在干旱半干旱的西北地区东部,降水再循环率整体偏低的情况下,其线性趋势增加非常显著。通过经验正交函数(EOF)分解的结果发现,降水再循环率的第一模态在2000年之前以负位相为主,而2000年之后以正位相为主,且从九年滑动平均来看降水再循环率呈先增加再减少的趋势。本研究依据降水再循环率的大小和气候倾向率的正负,将中国分出四类降水再循环率区域:降水再循环率较大且呈上升趋势(Ⅰ类),降水再循环率较大且呈下降趋势(Ⅱ类),降水再循环率较小且呈上升趋势(Ⅲ类),降水再循环率较小且呈下降趋势(Ⅳ类),并在四类区域中筛选出八个典型区域来研究降水再循环率对全球变暖的响应。在Ⅰ类和Ⅱ类区域的典型区域中的降水主要受到本地蒸发的影响,在Ⅲ类和Ⅳ类区域的典型区域中,降水与外来水汽输送之间的关系更为密切。在同一类型区域中内外循环各变量对全球变暖的响应值不同,蒸发量和水汽通量散度的变化会影响降水平流贡献和局地蒸发贡献对全球变暖的响应强弱。研究中国不同类型区域内外循环变量对全球变暖响应差异,有助于深化对气候变化影响的认识,为制定相应的气候适应策略提供科学依据。

全球升温1.5℃和2℃下中国群发性高温事件与人口暴露度预估

基于区域气候模式RegCM4对4个全球气候模式的动力降尺度模拟数据及未来人口预估数据,预估了SSP2-RCP4.5情景下全球升温1.5℃和2℃时,中国群发性高温事件(cluster high temperature events,CHTE)和CHTE人口暴露度的变化。结果表明:1.5℃和2℃升温阈值下,多模式集合(MME)预估CHTE年均频次相对于基准期分别增加31%和44%。不同强度事件中,严重CHTE事件的频次在1.5℃和2℃升温阈值下可分别增加约4.2倍和6.8倍。事件强度、持续时间、频次等指标趋向高值的发生概率更大。相对于2℃,1.5℃温升阈值下CHTE年均频次、持续时间和累计强度在全国大范围呈降低趋势,且表现出明显的区域性差异,年均频次的降幅自北到南递增,新疆和长江以南地区持续时间年均减少6 d以上(全国平均降幅为0.2 d),我国中东部地区累计强度年均减少20℃以上、新疆东部减少50℃以上(全国平均降幅为0.6℃)。此外,在1.5℃和2℃升温阈值下,MME预估CHTE影响人口的变化均呈现南增北减的空间分布,内蒙古地区略有减少,中东部地区普遍增加,全国总影响人口分别增加1.4倍和1.8倍。高温事件对城市的影响人口增幅更大(分别增加2.9倍和3.8倍),尤其是京津冀、长三角、珠三角、中原地区增幅最明显。全国的CHTE强度暴露度(分别增加2.2倍和5.2倍)和综合暴露度(分别增加1.2倍和1.8倍)呈明显增加趋势,特别是2℃升温阈值下城市的CHTE强度暴露度和综合暴露度的增幅分别高达10倍和4倍。

2019年7月28日宁夏区域性暴雨天气过程成因分析

【目的】分析此次暴雨过程的产生机制,以期为今后宁夏暴雨的预报提供参考。【方法】利用ECMWF ERA5的逐时再分析资料,通过环流分析和物理量诊断方法,揭示2019年7月28日宁夏区域性暴雨的产生成因。【结果】此次降水过程是在东高西低环流背景下,西风气流中小股冷空气南下遇副高西伸北抬,形成锋区造成的。副高外围的暖湿气流带来充沛的水汽为此次过程提供所需水汽。700 hPa、850 hPa的切变线及中低层的锋区满足此次降水过程提供了动力抬升条件,并叠加了不稳定能量。【结论】宁夏北部地区以锋区降水为主,中南部地区暖区中有对流云发展,配合锋面抬升,造成对流云叠加,降水强度增大。

海南岛双池玛珥湖沉积正构烷烃记录揭示的中世纪暖期气候环境特征

对采自海南岛双池玛珥湖的沉积岩芯(SCH17-04)进行了加速器质谱法(Accelerator Mass Spectrometry,AMS)^(14)C测年和正构烷烃组成的实验分析,据此探讨了中国热带北缘地区约775-1550年间的气候环境特征。结果表明,SCH17-04岩芯正构烷烃记录揭示了该湖沉积的有机质主要来自于陆生高等植物,也包含部分水生植物和菌藻类植物的输入;利用正构烷烃相关组分的比值发现,在中世纪暖期(Medieval Warm Period,MWP,约950-1350年)时,研究区草本植物比例明显增大,木本植物占比相对偏小,揭示出地处热带北缘的海南岛地区在中世纪暖期气候环境总体上较为偏干,而在黑暗时代冷期(Dark Ages Cold Period,DACP)晚期(约775-950年)和小冰期(Little Ice Age,LIA)早期(约1350-1550年),海南岛地区气候环境相对较为偏湿。区域对比分析发现,双池玛珥湖沉积正构烷烃记录与同处热带地区的雷州半岛湖光岩玛珥湖沉积、西沙群岛东岛湖泊沉积以及来自泰国的石笋记录等较为一致,都揭示了一个气候相对较为偏干的中世纪暖期,这可能跟同一时期热带辐合带(Intertropical Convergence Zone,ITCZ)南北迁移和热带雨带的扩张与收缩、太平洋东西部海区海表温度梯度变化等因素有关。

“22·06”广西暖区极端致洪暴雨成因与预报偏差分析

利用常规气象观测、多普勒天气雷达探测、卫星遥感及再分析等多源气象资料,通过统计及天气学诊断方法,对2022年6月17—21日广西暖区极端致洪暴雨过程成因与预报偏差进行分析。结果表明:(1)此次过程在高空槽、低涡切变、低空西南急流的共同影响下造成,以暖区对流性强降水为主。(2)强降水回波具有明显的后向传播特点,强回波带附近有偏北风和偏南风的辐合线,有利于对流系统的维持与发展,形成“列车效应”,造成局地极端强降水,桂北地形对强降水有增辐作用。(3)多个物理量的异常度分布对应着极端降水区域,其中K指数和整层可降水量与极端降水区域有较好的对应关系。(4)模式预报500 hPa高空槽强度偏弱、850 hPa急流位置偏差造成强降水落区位置偏西偏北、强度偏弱。

夏热冬暖地区住宅建筑运行阶段碳排放分析

随着“双碳”目标的提出,国家对建筑业的碳排放提出了更高的要求。由于住宅建筑的碳排放量占整个建筑业的48%左右,因此其相关研究对于我国“双碳”目标的实现以及人民生活和社会发展有着重要的现实意义。以夏热冬暖地区住宅小区调查数据为基础,分析影响住宅建筑碳排放的主要因素,并采用SPSS 25对碳排放数据进行偏相关分析和岭回归分析,建立夏热冬暖地区住宅建筑运行阶段碳排放的回归模型。结果表明:回归方程预测得出的小区住宅年平均碳排取量与实测数值差值为3.4%;夏热冬暖地区住宅建筑运行阶段对碳排放影响最大的是户内人口数,其次是建筑面积,建筑朝向对碳排放的影响较小;在过渡季节住宅建筑碳排放量相对较低,炎热的夏季是夏热冬暖地区碳排放的高峰。对夏热冬暖地区住宅建筑碳排放现状的研究可为该区域住宅建筑提供设计方案和运行指导,同时也可为该区域住宅建筑碳排放评估提供参考依据。

2023年4月闽南沿海一次暖区暴雨过程中尺度分析

本文利用常规和非常规资料对2023年4月18日闽南沿海地区一次特大暴雨过程进行了中尺度特征分析和研究。结果表明:此次特大暴雨过程是副高北抬和南风暖湿气流强迫背景下形成的强对流天气,东南季风绕过台湾省形成地形高压,南海水汽通道建立与弱冷空气触发是此次过程的降水机制。“列车效应”在雷达图中表现突出,针对区域性冷空气的入侵,风廓线雷达资料较常规资料更精细,地形正面阻挡对边界层偏南急流造成的暖区暴雨大值落区判断有指示意义。

夏热冬暖地区中小型建筑天井对建筑能耗的影响

这项研究旨在响应节能减排政策,通过对不同天井设计形式进行能耗真实物理模拟,探讨天井设计对建筑能耗的影响。模拟结果显示:(1)随着天井面积与建筑投影面积比例由4.89%增至24.95%,建筑单位面积全能耗由100.69 kWh/m^(2)增加至119.21 kWh/m^(2)。建筑全能耗和建筑体型系数呈正相关,可通过缩小建筑天井面积实现建筑整体节能。(2)天井深度对建筑单位面积全能耗影响不大。(3)不同几何形态对建筑单位面积全能耗影响不大。(4)天井形式影响建筑单位面积全能耗,开放式侧边天井能耗最低,其次为封闭式天井,开放式中央天井能耗最高。研究成果可用于指导天井类及中庭类建筑的建筑设计,以降低建筑整体能耗。本研究仅采用斯维尔软件进行实验,研究结果有待现实样本或不同软件对比的进一步确认和完善。

气候变暖影响下黄河源区潜在蒸发量预测不确定性研究

蒸发是连接地表能量平衡和水量平衡的重要纽带,高寒区蒸发量对气候变暖尤为敏感。然而,高寒区蒸发预测存在大量不确定因素,其造成流域水文循环变化规律分析、水资源管理面临严峻挑战。因此,以属于高寒区的黄河源区为例,利用5种物理机制不同的蒸发计算模型(P-M、Har、J-H、Mak和P-T)理清模型不确定性对流域潜在蒸发量预测结果的影响;通过耦合蒸发计算模型、GCMs模型、RCPs模型,探究多源不确定性对未来不同时期(近期、中期和远期)潜在蒸发量预测结果不确定性的影响,并利用方差分析方法量化评估各因素独立及交互作用对潜在蒸发量预测结果不确定性的贡献。结果表明:基于太阳辐射和气温的潜在蒸发量模型获得的潜在蒸发量明显大于基于物理机制P-M模型获得的潜在蒸发量,其差值约为150 mm;RCPs不确定性是导致蒸发预测结果不确定性的主导因素,占比高达65%,且多种不确定性因素的交互作用对蒸发预测结果不确定性的贡献在春、冬季节尤为突出。

Trends of Regional Precipitation and Their Control Mechanisms during 1979–2013

Trends in precipitation are critical to water resources. Considerable uncertainty remains concerning the trends of regional precipitation in response to global warming and their controlling mechanisms. Here, we use an interannual difference method to derive trends of regional precipitation from GPCP （Global Precipitation Climatology Project） data and MERRA （Modern- Era Retrospective Analysis for Research and Applications） reanalysis in the near-global domain of 60~ S-60~N during a major global warming period of 1979-2013. We find that trends of regional annual precipitation are primarily driven by changes in the top 30% heavy precipitation events, which in turn are controlled by changes in precipitable water in response to global warming, i.e., by thermodynamic processes. Significant drying trends are found in most parts of the U.S. and eastern Canada, the Middle East, and eastern South America, while significant increases in precipitation occur in northern Australia, southern Africa, western India and western China. In addition, as the climate warms there are extensive enhancements and expansions of the three major tropical precipitation centers-the Maritime Continent, Central America, and tropical Africa-leading to the observed widening of Hadley cells and a significant strengthening of the global hydrological cycle.

SWC-WARMS在重庆地区的降水预报性能分析

本文利用2 0 1 6 年5 - 7 月SWC-WARMS和CQMFS逐日2 0 时起报的2 4 h 累计降水预报资料及2 4 h 累计降水观测资料,对两家模式在重庆地区的24 - 4 8 h 和48 - 7 2 h 的2 4 h 累计降水预报结果进行客观检验评分和对比分析,并针对2 0 1 6 年5 - 7月重庆地区的8 次区域性强降水天气过程,进行了 SWC-WARMS的24-48 h 强降水落区和强度的主观检验,结果表明：对于24 - 4 8 h 累计降水,CQMFS的TS评分除暴雨和大暴雨量级外均优于SWC-WARMS,且相对于SWC-WARMS而言,空报较少,漏报较多;对于48 - 7 2 h 累计降水,各个量级降水的T S评分、空报率和漏报率的表现一致,SWC-WARMS的各项评分均明显优于CQMFS;对于重庆地区2 0 1 6 年5 - 7 月的8 次强降水天气过程,除个别个例预报较差外,SWC-WARMS对强降水落区和强度的预报均具有-定的指示意义,能为预报员提供有用的参考,但降水强度总体偏强,大暴雨量级的降水空报现象较为明显.