“Greatest lake period” and its palaeo-environment on the Tibetan Plateau

The “greatest lake period” means that the lakes are in the stage of their maximum areas. As the paleo lake shorelines are widely distributed in the lake basins on the Tibetan Plateau, the lake areas during the “greatest lake period” may be inferred by the last highest lake shorelines. They are several, even tens times larger than that at present. According to the analyses of tens of lakes on the Plateau, most dating data fell into the range of 40-25 ka BP, some lasted to 20 ka BP. It was corresponded to the stage 3 of marine isotope and interstitial of last glaciation. The occurrence of maximum areas of lakes marked the very humid period on the Plateau and was also related to the stronger summer monsoon during that period.

The Dry-Cold Climate of the Qijia Archeological Civilization in Chankou of the Loess Plateau along the Silk Road Since the Neolithic Period

Objective Large numbers of archeological relics from the Neolithic period are widely distributed in all tributaries of the Yellow River. The early humans tended to reside along the river valleys, and developed small but characteristically decentralized ancient valley culture. It is universally acknowledged that the agriculture exchange between China and western countries and the moderate

Different characteristics of the structure of atmospheric boundary layer between dry and rainy periods over the northern Tibetan Plateau

In this paper, based on in-situ observational data of the Coordinated Enhanced Observing Period （CEOP） Asia-Australia Monsoon Project （CAMP） on the Tibetan＇Plateau （CAMP-Tibet）, structure of the Atmospheric Boundary Layer （ABL） was preliminarily studied during the dry and rainy seasons. The main results show： （a） Diurnal variation of the ABL is obvious over the northern Tibetan Plateau area. The height of the ABL is different with the season change, which ranges from 2,211 m to 4,430 m during the pre-monsoon season and from 1,006 m to 2,212 m during the monsoon season. The ABL height is higher during the dry period than during the rainyigeriod. （b） The humidity is lower during the dry period than during the rainy period, and there are reverse humidity during both periods. （c） Horizontal wind direction is mostly west during the dry period, east under the height of 2,500 m and west above the height of 2,500 m during the rainy period. The wind speed is low during both the rainy and dry periods in the lower ABL layer. The wind speed is stronger within the upper ABL during the dry period than dtn-ing the rainy period.

黄河水沙变化:历史、现状与未来

在现状防洪工程格局下,实现长治久安,核心在于黄河下游能否长期“河床不抬高”,而决定河床淤积抬高的关键因素是水沙条件。本文分析了2200多年来黄河下游决溢频次、黄土高原气候和社会环境变化,利用史料、前人研究成果和实测数据等,对不同历史时期黄河水沙的变化情况进行了分析。研究表明,从西汉时期至1970年代,黄河水沙量总体呈现为“水量越来越少、沙量越来越多”的趋势:在东汉故道行河的前837年(公元70—907年),黄河沙量只有4亿~5.5亿t/a、下游水量超600亿m^(3)/a,随后的127年黄河沙量增至7亿t/a左右、下游水量减至580亿m^(3)/a;1579—1918年黄河沙量增加到15亿t/a、下游水量减至570亿m^(3)/a;1933—1979年是黄土高原产沙最丰的时期,黄河潼关站实测输沙量为16.2亿t/a,若还原坝库拦沙后“天然”输沙量达19.2亿t/a。1980年代至今,黄河水沙呈现出“水沙均减”的趋势,其中,2000—2023年潼关站实测输沙量为2.34亿t/a,还原坝库拦沙后“天然”输沙量为5.5亿t/a,与唐代持平,下游实测径流量290亿m^(3)/a,是唐末的46%。未来,依靠持之以恒的水土保持,黄河沙量或许可以长期控制在4亿~5亿t/a,达到东汉故道行河前期的来沙水平,但因下游来水量难超270亿m^(3)/a,黄河下游现行河道的行河寿命难以比肩东汉故道。

Climate Change Characteristics and Return Periods of Heavy Precipitation in the Northeast Side of Qinghai-Tibet Plateau

[ Objective] The study aimed to discuss analyze climate change characteristics and return periods of heavy precipitation in the northeast side of Qinghai-Tibet Plateau. [ Method] Based on the data of daily precipitation from 1943 to 2008 in 6 representative meteorological stations in Linxia located in the northeast side of Qinghai-Tibet Plateau, the climate change characteristics of heavy precipitation were analyzed, and the return periods of heavy precipitation were calculated by Pearson-Ill probability distribution method. [ Result] Days of heavy precipitation in Linxia region in- creased conspicuously since the 1990s. The return periods of heavy precipitation in the six stations on August 20, 2008 were consistent with the re- sults of artificial estimation. [ Conclusion] The research could provide scientific references for the reasonable utilization of climate resources, disas- ter prevention and rational arranqement of anricultural plantina svstems in Linxia reaion.

基于CMIP6多模式的黄土高原气温变化模拟评估及情景预估

[目的]明晰黄土高原未来气温增加趋势和幅度,以期为黄土高原未来气温变化决策事件和防洪减灾等提供参考。[方法]基于第六次国际耦合模式比较计划(CMIP6)中的22个地球-气候系统模式的模拟结果,通过观测数据系统评估了各模式历史时期(1961—2014年)模拟能力后,选用较好的10个模式的集合平均,对不同共享社会经济路径(SSPs)下黄土高原2015—2100年气温的时空变化特征进行了分析。[结果]在SSP1-2.6,SSP2-4.5,SSP3-7.0和SSP5-8.5情景下,2015—2100年黄土高原增温速率分别达到了0.09℃/10 a,0.28℃/10 a,0.48℃/10 a,0.66℃/10 a,且相对于1995—2014年,2081—2100年增温分别达1.53℃,2.69℃,3.83℃,5.25℃。除SSP1-2.6情景外,其余情景增温已远远超过《巴黎协定》全球2℃升温的目标,而且在SSP5-8.5情景下,2041—2060年增温已达2.44℃。SSP5-8.5情景下,2081—2100年黄土高原春、夏、秋和冬季气温相对于1995—2014年增温幅度变化范围为3.83~4.75℃,4.75~5.67℃,4.98~5.67℃,4.29~5.67℃。[结论]未来黄土高原将面临强大的增温压力,排放情景越高增温越显著,未来应加强对黄土高原气温的观测研究。

采收期对烟富3号苹果果实品质的影响

以15年生烟富3号苹果为试材,研究了甘肃省陇东旱塬区6个采收期(2022年10月5日、10月11日、10月17日、10月23日、10月29日、11月5日)果实低温贮藏时品质生理变化规律及特性。结果表明:随着采收期的推迟,果形指数无显著变化,果实纵径、横径、可溶性固形物含量、可溶性糖含量及固酸比、糖酸比、糖心率均显著增加,硬度及可滴定酸含量、总酚含量显著降低,10月23日采收的果实单果重最大、着色最好、维生素C含量最高,可溶性固形物含量达15.13%。低温贮藏期间,不同采收期果实硬度及可滴定酸含量、维生素C含量均不断下降,可溶性固形物含量先升高后下降,总酚含量先下降后升高,果实呼吸强度、乙烯释放速率均在贮藏120 d时出现峰值;10月17日采收的果实硬度及可滴定酸含量、维生素C含量下降幅度较小,果面光洁度保持稳定,贮藏180 d后,果实硬度、可溶性固形物含量、维生素C含量、L^(*)值均最高,果实呼吸强度、乙烯释放速率峰值、失重率、腐烂率均最低。综合分析,10月23日可作为甘肃省陇东旱塬区烟富3号果实鲜食的最适宜采收期,10月17日可作为长期低温贮藏的最佳采收期。

云南高原金沙江干支流水沙相关性分析

云南省境内的金沙江流域覆盖全省主要的经济、政治地域,金沙江虎跳峡河段是正在开工建设的滇中引水工程的水源区,分析云南高原金沙江干支流水沙相关性对揭示区域水沙规律、保障水源安全具有重要意义。为此,基于云南省境内金沙江流域干流及典型支流上的控制站点的流量和悬移质含沙量等观测资料,依托随机水文、趋势分析、Copula函数等方法系统地分析了水沙年际年内分布、时空遭遇、协同变化等规律和特性。结果表明,云南省境内金沙江干、支流流量和悬移质含沙量的年内分配不均,流量和悬移质含沙量正相关变化不完全同步;流域发生连续丰水/多沙事件的概率大于连续枯水/少沙事件的概率,但前者的持续影响弱于后者;水沙遭遇异步概率大于同步概率,丰水多沙组合的同现重现期最大、联合重现期次之、条件重现期最小。

黄土高原近30年降水集中度分析及时空演变特征

选取近30年的黄土高原地区58个气象站点的降水数据,分析了黄土高原年降水以及降水集中度(PCD)和集中期(PCP)的时空变化特征,结果表明:(1)黄土高原地区年均降水量在50~900 mm,空间分布上东南高西北低。降水高值区分布在三门峡站与武功站附近以及五台山站,年均降水量为900 mm;低值区位于临河站附近,年均降水量为50 mm;(2)黄土高原地区的降水集中度分布于0.43~0.76,自东南向西北递增;而降水集中期的变化则不太明显,多集中于夏季的7-8月份。因此在降水集中的7-8月份,水土流失会比较加重,应加强水土流失防治工程,在降水量大的月份做好灾害防护,为工农业生产提供预警,减少工农业生产损失与经济损失。

关节镜下经皮空心螺钉内固定治疗SchatzkertⅠ~Ⅲ型胫骨平台骨折术后恢复与预后分析

目的分析对比关节镜下经皮空心螺钉内固定和传统切开复位内固定治疗SchatzkertⅠ~Ⅲ型胫骨平台骨折的术后恢复以及不同时间预后效果差异。方法选择2021年1月至2023年12月南阳医学高等专科学校第一附属医院收治的114例胫骨平台骨折患者,根据治疗方法分为两组,对照组55例开展传统切开复位内固定术,观察组59例开展关节镜辅助下经皮空心螺钉内固定术。比较两组患者围手术期指标、术后恢复情况,以及出院前、术后1个月和术后6个月疼痛程度、下肢功能、膝关节功能和日常生活能力水平变化。结果观察组患者术中出血量和术后引流量均明显少于对照组,差异有统计学意义(P<0.05)。观察组手术时间、下地时间、总住院时间、术后负重下地所用时间和骨折愈合时间均于对照组,差异有统计学意义(P<0.05)。出院前、术后1个月和术后6个月观察组患者视觉模拟评分法(VAS)评分均低于对照组,差异有统计学意义(P<0.05);两组出院前LEFS评分比较差异无统计学意义(P>0.05);术后1个月、术后6个月,观察组LEFS评分高于对照组,差异有统计学意义(P<0.05)。观察组出院前、术后1个月和术后6个月KSS评分均高于对照组,差异有统计学意义(P<0.05)。结论在关节镜辅助下开展经皮空心螺钉内固定术治疗胫骨平台骨折较传统切开复位内固定术更理想,不仅体现在前者围手术期指标更具优越性,前者术后恢复程度也相对更快,疼痛感减轻明显,并且术后运动功能和日常生活能力改善更明显。

“土著”细菌浸种对禾本科牧草不同生长期的影响

为筛选促进禾本科牧草生长的菌株,本研究选用分离自青藏高原细菌3属(芽孢杆菌属、假单胞菌属和沙雷氏菌)的10株“土著”菌株制备菌液,浸种牧草种子(同德短芒披碱草、青海中华羊茅、青海草地早熟禾与青海冷地早熟禾),研究不同生长期细菌对牧草生长、生理及生化指标的影响。结果表明:枯草芽孢杆菌B1在4种牧草萌发期不同程度提高了萌发率、萌发势、根长、芽长,在盆栽幼苗期提高了根长、株高、鲜重及干重;假单胞菌B16对4种牧草萌发期根长、芽长和盆栽期根长、株高具有显著促进作用。返青期结果表明:假单胞菌B16显著促进青海草地早熟禾与青海冷地早熟禾返青期的自然高度(18.97%~31.25%)与盖度(11.11%~14.63%)。因此,Bacillus subtilisB1和Pseudomonassp.L1-44-08 B16为最具有促生抗逆潜能与应用前景的菌株。该结果为青藏高原草业及草场退化治理提供新思路。

Paleoclimate Changes during the Early Oligocene in the Hoh Xil Region, Northern Tibetan Plateau

Sedimentological, cyclic-stratigraphic, paleomagnetic, and clay-mineralogical studies on the early Oligocene Yaxicuo Group in the Hoh Xil Basin, the largest Cenozoic sedimentary basin in the hinterland of the Tibetan Plateau, provide abundant information of paleoclimate changes. A 350-m thick section in the middle-lower Yaxicuo Group was analyzed to reveal the climatic history that occurred in the Hoh Xil region during the early Oligocene interval 31.30-30.35 Ma, dated with the paleomagnetic chronostratigraphy. The results indicate that arid and cold climate dominated the Hoh Xil region during the early Oligocene in general, being related to the global cooling and drying events that occurred in the earliest Oligocene. Within this period, relatively warm and wet climate accompanied by strong tectonic activity occurred in the 31.05-30.75 Ma interval; while arid and cold climate and relatively inactive tectonics occurred in the 31.30-31.05 and 30.75-30.35 Ma intervals. Furthermore, spectral analyses of high-temporal resolution paleoclimatic records show orbital periods including eccentricity, obliquity, and precession. It is concluded that paleoclimate changes during the early Oligocene in the Hoh Xil region were forced by both tectonic activity and orbital periods.

装配式建筑室内环境与能耗综合评价

装配式建筑作为一种便捷、新兴的建筑形式,值得大力推广。综合评价分析装配式建筑室内热环境、空气质量、能耗等。需要考虑装配式建筑室内温度分布、气流组织和能源系统。根据DeST软件的模拟结果,提出了不同围护结构符合不同气候区室内热环境的平均温度标准(18℃)。以夏热冬冷地区为例,利用ANSYS Fluent软件探究室内温度、风速的分布以及室内污染颗粒物的排放特性。并对装配式辅助建筑的供能系统及系统运行性能和成本构成进行研究。结果表明,在冬季(4.1℃)和夏季(31.1℃)典型日的室内平均温度条件下,出于考虑人体热舒适需求,应启动空气源热泵。此外,污染颗粒释放后室内空气质量能够满足洁净度标准。

CRUST AND UPPER STRUCTURE OF QINGHAI-TIBET PLATEAU AND ITS ADJACENT REGIONS FROM SURFACE WAVEFORM INVERSION

In this paper,218 long period Rayleigh wave records from 7 seismic station of CDSN are selected.We applied a partitioned waveform inversion to these data in order to construct a 3\|D model of shear velocity down to 400km depth in the crust and upper mantle of Qinghai\|Tibet plateau and Its Adjacent Regions (22°～44°N,70°～110°E).The first step of the waveform inversion used involved the matching of the waveforms of fundamental and highermost Ravleigh waves with waveforms synthesized from stratified models;in the second stage,the 3\|D model was constructed by solve linear constrains equation. The major structural features inferred from the surface waveform inversions can be summarized as follows:(1) There is a great contrast between surface waveform through Qinghai—Thibet plateau and the others.Main frequency of the former is lower than the latter, which indicate the crust depth of Qinghai—Tibet plateau is deeper than the others. In addition,the amplitude of about 30s period and 50s period is lower than both sides,which implied these exist lower velocity layer at about 25km depth and about 50km depth in Qinghai—Tibet plateau Crust.The former is common,the latter was argued because resolution of most method can not prove it.

The property, age and formation environment of the palaeokarst in Qinghai-Xizang Plateau

The karst landforms distributed on the Qinghai-Xizang (Tibet) Plateau can be genetically classed with the Tertiary underground karst, which were gradually exhumed to the surface with the uplift of the plateau during Quaternary period. The relative deposits of the Tertiary palaeokarst processes, such as the residuum and speleothem, were discovered recently in the southern and southeastern fringe areas of the plateau, where has geological-currently been disintegrated by the headward erosion processes of the modern river systems. The major chemical components of the clay portion of the residuum consist mainly of SiO2, Al2O3 and Fe2O3. The clay minerals composition of the clay portion belongs to illite-kaolinite pattern for most of the residuum samples, and kaolinite-illite pattern for a few of the samples. It can be judged from the silicic acid index and the clay minerals composition that the formation of the residuum of the Plateau was in its initial phase. However, such a lower chemical weathering index only reflected the weathering degree in the bottom or lower parts of the lateritic weathering crust. The relatively intensive chemical weathering processes of the surface layers of the lateritic weathering crust could be logically speculated. The surface feature textures of quartz grains in the residuum were formed mainly by the chemical erosion, which revealed a long-term humid-tropical environment when the residuum and the palaeokarst formed.

气候变暖对晋北黄土高原半干旱区马铃薯适播期的影响

以气候变暖为主要特征的气候变化对马铃薯物候期、生长发育及产量都产生很大影响,研究马铃薯生长季热量资源和适播期变化特征,对调整品种布局和合理利用气候资源具有重要意义。利用1981—2016年晋北地区地面气象观测站和农业气象观测站资料,通过趋势分析和相关分析,研究晋北马铃薯气候资源变化特征及对马铃薯产量的影响;基于积温稳定性原理,建立气象产量预测模型,得出最高气象产量对应的适播期,并分析适播期的年代变化特征。结果表明,晋北马铃薯生长季气温以0.32℃·10a^(-1)速率呈升温趋势,≥5℃积温以47.0℃·d·10a^(-1)速率呈增加趋势。气候变暖背景下对晋北马铃薯产量影响显著的气候因子主要是出苗~分枝期的平均气温,全生育期的积温、日照时数、需水量,出苗~分枝期、花序形成~可收期及全生育期的最高气温≥30℃的日数。气温和日照基本为负效应,降水在营养生长期为负效应,生殖生长期为正效应。晋北马铃薯适播期随着气候变暖有提前的趋势,20世纪80年代适播期在5月上旬末至5月中旬,90年代适播期在5月上旬,21世纪最初10 a适播期在4月下旬至5月上旬初,2010年以后马铃薯适播期提前到4月中旬末至4月下旬。建议晋北黄土高原半干旱区盆地地区种植中晚熟品种,尽量选择早播,可以选择4月中旬末至4月下旬,高海拔地区建议种植中熟品种或采取地膜覆盖提早播期来种植中晚熟品种,可以在4月下旬末至5月上旬播种。

青藏高原非冻结期观测的土壤湿度和模式产品的对比分析

对第三次青藏高原大气科学试验(TIPEX-III)的土壤湿度观测资料与ERA5、ERA-Interim、MERRA-2、NOAH2.1和CFSv2模式或再分析产品(简称模式产品)的土壤湿度在非冻结期(410月)的时空分布特征及相关系数、无偏均方根误差和标准偏差比的对比分析结果表明:(1)五套模式产品均能表现青藏高原西部偏干、东部偏湿的空间分布特点,以及青藏高原西部月尺度的土壤湿度与降水的关系。(2)五套模式产品与观测的日平均土壤湿度的相关性,高原西部的明显高于高原东部的;ERA5与观测的土壤湿度相关性最好,但是无偏均方根误差较大,尤其是在青藏高原西部;ERA-Interim的无偏均方根误差最小,但其相关性较低。(3)五套模式产品均高估了高原西部土壤湿度的变化幅度,低估了高原东部土壤湿度的变化幅度。

黄土高原半干旱区气候变化对荞麦生产的影响

基于2009-2019年甘肃中部半干旱区的定位观测试验,根据气象观测资料,采用线性回归分析、相关分析和通径分析研究气候变化对黄土高原荞麦生育期及产量的影响。结果表明,黄土高原半干旱区苦荞全生育期内气温极显著降低,气候变化倾向率为-0.81℃·10a^(-1)(P<0.01),降水量极显著增多,气候变化倾向率为48.55mm·10a^(-1)(P<0.01),日照时数极显著增加,气候变化倾向率为4.76h·10a^(-1)(P<0.01);甜荞全生育期内气温极显著降低,气候变化倾向率为-0.82℃·10a^(-1)(P<0.01),降水量极显著增多,气候变化倾向率为33.33mm·10a^(-1)(P<0.01),日照时数极显著减少,气候变化倾向率为-28.98h·10a^(-1)(P<0.01);甜荞、苦荞全生育期分别以0.53d·a^(-1)和0.84d·a^(-1)的速率显著缩短;甜荞、苦荞营养生长期随气温及日照时数增加而缩短,随降水量增多而延长,生殖生长期随气温及日照时数增加而延长,随降水量增多而缩短;研究期内苦荞产量增加,产量与全生育期内气温和日照时数分别呈极显著和显著负相关,与降水量呈显著正相关,气温是影响苦荞产量形成的关键因子;研究期内甜荞产量下降,产量与全生育期内气温、降水量及日照时数均呈显著正相关,全生育期气温和日照时数是影响甜荞产量形成的关键因子。

长江源区年际冰水情变化及其影响因子分析

受限于高寒山区地形、气候和环境条件,目前关于长江源区河流的冰水情研究较少,源区降雨径流年际变化和冰盖分布等规律不明确。为了明晰长江源区水文与水资源现状和冰水情本底,本文收集整理了2006—2018年沱沱河和直门达水文站近十年的降雨、蒸发、径流、水温、气温和冰厚资料,采用统计分析、线性回归、单一因子分析和相关性分析等结合的研究方法,重点揭示了源区河流流量、冰期和冰厚现状、其年际变化特征和主要影响因子。研究表明,源区河流洪峰年际波动范围超50%,洪峰集中在7—9月,非汛期流量仅为汛期流量的1/7,非汛期流量年际波动小于汛期,且直门达站水位流量年际变化幅度小于上游沱沱河站;沱沱河站冰期持续时间7个月,而下游直门达站冰期为5个月,多年平均冰盖厚为0.15 m,造成两站冰情差异的主要原因是源区垂直地形急变引起的高程差;源区降雨量年际波动与年际径流波动一致,蒸发量年际波动仅为降雨量的一半,因此两站流量的年际波动受降雨影响较大。长江源区降雨和气温变化是冰水情变化的主要驱动因子,与源区河流的地形高程密切相关,亟需系统的科考进一步明晰长江源冰水情时空变化规律。