Risk prevention and control strategies for the severely affected areas of snow disaster in the Three Rivers Source Region(TRSR), China

Historically,frequent and heavy snow disaster(SD)has caused serious livestock death and casualties,resulting in a devastating impact on animal husbandry development in the Three Rivers Source Region(TRSR).From winter in 2018 to spring in 2019,the largest SD occurred in this area over the past 10 years,especially in core zones of the Lancang River Source Region.Field research results show that the main causes of the major SD include weak infrastructure(i.e.,roads,communications,warm sheds,and insufficient forage reserve),low rate of domestic animals for sale before the SD,and low loss settlement rate.SD occurrence could furtherly reduce the ability of disaster prevention,mitigation and relief of disaster loss.In the future,heavily affected SD areas should improve the forecasting ability of snowfall incidents,strengthen infrastructure construction,implement grass and livestock balance strategies,optimize livestock structure,improve loss settlement rate,and develop a modern compound model of animal husbandry development model that combines breeding,slaughtering and deep processing of animal product.

Evaluation of Forest Damaged Area and Severity Caused by Ice-snow Frozen Disasters over Southern China with Remote Sensing

The accurate assessment of forest damage is important basis for the forest post-disaster recovery process and ecosystem management. This study evaluates the spatial distribution of damaged forest and its damaged severity caused by ice-snow disaster that occurred in southern China during January 10 to February 2 in 2008. The moderate-resolution imaging spectroradiometer(MODIS)13 Q1 products are used, which include two vegetation indices data of NDVI(Normalized Difference Vegetation Index) and EVI(Enhanced Vegetation Index). Furtherly, after Quality Screening(QS) and Savizky-Golay(S-G) filtering of MODIS 13 Q1 data, four evaluation indices are obtained, which are NDVI with QS(QSNDVI), EVI with QS(QSEVI), NDVI with S-G filtering(SGNDVI) and EVI with S-G filtering(SGEVI). The study provides a new way of firstly determining the threshold for each image pixel for damaged forest evaluation, by computing the pre-disaster reference value and change threshold with vegetation index from remote sensing data. Results show obvious improvement with the new way for forest damage evaluation, evaluation result of forest damage is much close to the field survey data with standard error of only 0.95 and 1/3 less than the result that evaluated from other threshold method. Comparatively, the QSNDVI shows better performance than other three indices on evaluating forest damages. The evaluated result with QSNDVI shows that the severe, moderate, mild damaged rates of Southern China forests are 47.33%, 34.15%, 18.52%, respectively. By analyzing the influence of topographic and meteorological factors on forest-vegetation damage, we found that the precipitation on freezing days has greater impact on forest-vegetation damage, which is regarded as the most important factor. This study could be a scientific and reliable reference for evaluating the forest damages from ice-snow frozen disasters.

Vulnerability Assessment of Snow Disaster Based on Traffic System:A Case Study of Chenzhou City in Hunan Province,China

The article establishes the patterns of urban snow disaster system and disaster chain based on the theory of regional disaster system. The patterns indicate that urban snow disaster is exacerbated mainly through the traffic system. In addition, the paper sets up the vulnerability assessment index system and synthetically vulnerability assessment model of urban snow disaster which are mainly based on traffic system, and applies them in Chenzhou City. The results of assessment indicate that obvious geographical differences exist in the vulnerability of snow disaster bearing bodies: vulnerability of Chenzhou section of the Beijing-Zhuhai expressway is the highest in Chenzhou City, and the southeastern counties are more vulnerable than the northwest region. Furthermore, according to the snow disaster vulnerability dynamic process analysis, the vulnerability of Chenzhou City obviously increased in 2008 winter compared with that in 2007. Finally, the paper presents some suggestions for the locations of the emergency commands and the reserves of relief materials based on the evaluation results, and points out that disaster monitoring and relevant technical level should be strengthened for the minimization of traffic system's vulnerability.

Early Warning of Snow Disaster in Pasturing Areas of Inner Mongolia

Using ground and remote sensing monitoring, and national standards of snow disaster monitoring evaluation standards, quantitative evaluation of snow disaster was realized. Threshold of animal husbandry weather forecast indexes were applied to establish snow disaster early warning for different grasslands in pasturing areas of Inner Mongolia, and make the grade distribution map of snow disaster early warning. The forecast results basically met the real conditions, it proved that this forecast method was capable of evaluating scale and influence degree of snow disaster. However, the snow disaster grade forecast deviated from the real conditions for the influence of weather forecast accuracy rate.

Potential Hazard Map for Snow Disaster Prevention Using GIS-Based Weighted Linear Combination Analysis and Remote Sensing Techniques: A Case Study in Northern Xinjiang, China

Snow disaster is one of the top ten natural disasters worldwide. Almost every year, there will be snow disasters in north Xinjiang, northwestern China. Since the accumulated heavy snow in winter season will seriously threaten people’s lives, the main object of this study is to produce a potential hazard map for snow avalanche prevention. Taking three snow seasons from November to March of year 2008 to 2010, potential hazard areas were estimated, based on snow volume products and terrain features. Remote sensing (RS) techniques and geographical information system (GIS) based weighted linear combination (WLC) approach were applied, taking into consideration multiple criteria. Snow avalanche risks were analyzed using physical exposure and vulnerability indexes. The analysis indicates that: the areas at high-risk of avalanches are located in the north and south part of the counties of Altay, Bortala and Ili prefectures;the areas at medium-risk of avalanches are found in the certain part of Altay prefecture and Urumqi, Changji, Tacheng prefectures;the avalanche risk is generally low throughout the large area to the certain part of the study area and the region on the border of the eastern north Xinjiang. Overall, the risks of snow avalanche in Altay and Ili prefectures are higher than that other regions;those areas should be allocated correspondingly more salvage materials.

“里和”与“外应”:气候变化下环湖地区的适应性治理

气候变化给青藏高原带来显著影响,更是对当地农牧民的生计造成冲击,研究当地气候变化影响及牧民应对策略,不仅是提高气候变化适应能力的起点,也是建立适应气候变化区域格局的重要支撑。基于2020和2023年对案例地Z村的两次实地调研,通过牧户问卷调查和深度访谈,按照适应性治理的三层特征,分析当地气候变化适应的成效与挑战。研究发现:面对降水和气温的变化、湖面扩大、植被变化和灾害影响,牧民积极采取多种办法来减少气候变化的影响,呈现较高的适应性与恢复力。这些适应行动的成功经验源于“里和”,包括人与人之间的合作以及人与自然间的和谐律动。但是“外应”不足仍是挑战,即案例地缺少必要的外部支持,不仅包括直接灾害救助,还包括对其适应能力可持续性的保护和应对潜在的草原生态变化。如果“外应”持续低迷,现有的适应能力终会耗尽。提出建立适应气候变化区域格局应遵循多中心治理的思路,将多个利益相关者联合起来,汇总不同地区气候变化应对的成功经验,形成多种知识的融合,才能形成对地方的有效“外应”,提高中国气候变化适应能力。

基于RBF网络的新疆特重雪灾区最大积雪深度预测研究

基于建立的雪灾灾损指数,确定新疆特重雪灾区域;进一步聚焦特重雪灾区的8个县(市),包括阿勒泰市、福海县、青河县、塔城市、托里县、沙湾市、尼勒克县和伊宁县,分别建立县域RBF网络模型,预测2021—2050年年最大积雪深度。结果表明:该模型可用于新疆特重雪灾区最大积雪深度预测,但预测精度仍有待提升;塔城市、尼勒克县将于2025—2029年连续出现最大积雪深度偏高事件,2039年青河县将出现最大积雪深度的极大值,因此应关注可能发生雪灾的年份与县(市),积极做好雪灾的防御工作。

九连山常绿阔叶林区系动态特征及其对雪灾的响应

【目的】旨在探究九连山常绿阔叶林的区系动态特征,以及2008年雪灾对九连山植被区系特征的影响。【方法】基于九连山6 hm2样地、车八岭20 hm2样地、鼎湖山20 hm2样地、古田山24 hm2样地以及天童20 hm2样地的调查数据,探讨空间尺度上的区系特征差异;基于2008年重大雪灾时建立的九连山4 hm2样地和2022年的复查数据,探讨雪灾对植被区系的时间动态影响。【结果】九连山6hm2样地的木本植物有25061株,分属50科92属213种,热带分布类型和温带分布类型的科分别占总科数的52%和22%,热带分布类型和温带分布类型的属分别占总属数的68%和30%,与其他样地种的相似性均低于50%。与其他样地相比,九连山6hm2样地的面积最小,物种数却最多。与2008年九连山4 hm2样地相比,2022年九连山4 hm2样地消失了12科23属49种,新增了1科7属29种,且相似性系数极高。【结论】九连山植被处于南亚热带与中亚热带的植被过渡地带,偏向于中亚热带,是一个物种保存丰富、特异性和分化程度较高的区域。2008年重大雪灾对九连山常绿阔叶林产生了一定程度的干扰,历经14年仍未完全恢复。

路堑风吹雪灾害的形成和防治研究

风吹雪灾害是一种寒冷山区交通线路比较常见的自然灾害,现场调研发现路堑是风吹雪灾害最为严重的路基形式之一。本文针对路堑风吹雪灾害的形成和防治展开研究,基于Euler-Euler方法和Mixture模型模拟风雪两相流,同时利用现场实测数据验证模拟结果。研究典型路堑风吹雪灾害中风雪分布的演化过程,并比较分析不同形式路堑的风吹雪灾害特征,结果发现两侧边坡比小于1∶2的路堑风吹雪灾害最为严重。该类路堑严重的风雪灾害的形成原因是两侧边坡积雪的增加压缩了路面旋涡尺度,进而削弱了旋涡的回流加速作用。同时发现雪檐在推进到上风侧边坡中点前为安全储备期,此时上风侧边坡积雪量即为临界储雪量。

S319布吉公路风吹雪灾害防治技术措施研究

S319布尔津至吉木乃口岸公路工程第二合同段沿线部分段落范围内存在较严重风吹雪灾害。通过调查气象、积雪分布,现场监测风吹雪情况,结合地理地形条件、风速风向、水文地质,对风吹雪灾害形成特征进行详细分析。最终,从路线选线、路基断面、路基填挖高度、工程防治措施等方面进行综合防治,为公路风吹雪灾害防治提供参考。

Characteristics and hazards of different snow avalanche types in a continental snow climate region in the Central Tianshan Mountains

Snow avalanches are a common natural hazard in many countries with seasonally snow-covered mountains.The avalanche hazard varies with snow avalanche type in different snow climate regions and at different times.The ability to understand the characteristics of avalanche activity and hazards of different snow avalanche types is a prerequisite for improving avalanche disaster management in the mid-altitude region of the Central Tianshan Mountains.In this study,we collected data related to avalanche,snowpack,and meteorology during four snow seasons(from 2015 to 2019),and analysed the characteristics and hazards of different types of avalanches.The snow climate of the mid-altitude region of the Central Tianshan Mountains was examined using a snow climate classification scheme,and the results showed that the mountain range has a continental snow climate.To quantify the hazards of different types of avalanches and describe their situation over time in the continental snow climate region,this study used the avalanche hazard degree to assess the hazards of four types of avalanches,i.e.,full-depth dry snow avalanches,full-depth wet snow avalanches,surface-layer dry snow avalanches,and surface-layer wet snow avalanches.The results indicated that surface-layer dry snow avalanches were characterized by large sizes and high release frequencies,which made them having the highest avalanche hazard degree in the Central Tianshan Mountains with a continental snow climate.The overall avalanche hazard showed a single peak pattern over time during the snow season,and the greatest hazard occurred in the second half of February when the snowpack was deep and the temperature increased.This study can help the disaster and emergency management departments rationally arrange avalanche relief resources and develop avalanche prevention strategies.

Snow Cover Monitoring Method by Using HJ-1Satellite Data

Environment and Disasters Monitoring Microsatellite Constellation with high spatial resolution,high temporal resolution and high spectral resolution characteristics was put forward by China.HJ-1B satellite,one of the first two small optical satellites,had a CCD camera and an infrared camera,which would provide an important new data source for snow monitoring.In the present paper,through analyzing the sensor and data characteristics of HJ-1B,we proposed a new infrared normalized difference snow index(INDSI) referring to the traditional normalized difference snow index(NDSI).The accuracy of these two automatic snow recognition methods was estimated based on a supervised classification method.The accuracy of the traditional NDSI method was 97.761 9% while that of the new INDSI method was 98.617 1%.

透风率及积雪形态对防雪栅防护效果的影响

针对道路风吹雪灾害的工程防雪措施,采用数值模拟与现场实测相结合的方法,系统研究防雪栅透风率和不同阶段积雪形态对防雪栅周边流场的影响特性,分析不同阶段积雪的形成机理,得到防雪栅周边积雪的演化规律。结果表明:随着防雪栅透风率的增加,防雪栅背风侧低速区以及旋涡范围逐渐缩小,雪颗粒堆积的速度变慢,对于不同透风率的防雪栅,积雪均最先在其背风侧5 H~9 H范围内发生沉积(H为防雪栅高度),并逐渐向两侧延伸;防雪栅底部间隙使得气流在防雪栅底部被加速,雪颗粒不易沉积,有效延长了防雪栅被积雪掩埋的时间;防雪栅两侧-2.5 H~18 H范围雪颗粒均会发生沉积,随着积雪厚度的不断增加,积雪的增长速率逐渐趋缓。

伊犁地区酿酒葡萄农业气候特征分析

利用新疆维吾尔自治区伊犁哈萨克自治州酿酒葡萄可种植区10个气象站点逐日气象和酿酒葡萄生育期数据,通过M-K检验、趋势检验等统计方法,结合ArcGIS空间表达,分析了1961-2020年研究区酿酒葡萄气候资源和农业气象灾害的时空变化特征,为高效合理利用当地积雪资源,缓解干旱及冻害,优化酿酒葡萄越冬方式,选择成本较低的积雪覆盖方式提供科学依据。结果表明:(1)1961-2020年伊犁地区除昭苏及尼勒克部分区域外光热资源丰富,年均降水量空间分布不均且低于455mm,全区年均降水量以5.1mm·10a-1趋势增加,总体满足酿酒葡萄生长发育需求;全区酿酒葡萄越冬期(11月-翌年3月)降雪每10a增加7.4mm,且被0-10cm积雪覆盖的概率大于90%;(2)1961-2020年全区越冬期冻害频次、强度均有所下降,潜在生长季(4-10月)中7月和9月旱情较严重。

Risk analysis of snow disaster in the pastoral areas of the Qinghai-Tibet Plateau

Snow disaster is one of the top ten natural disasters worldwide, and the most se- vere natural disaster to affect the pastoral areas of the Qinghai-Tibet Plateau. Based on the hazard harmfulness data collected from historical records and data collected from entities affected by this hazard in 2010, a comprehensive analysis of the 18 indexes of snow disaster on the Qinghai-Tibet Plateau was conducted, encompassing the hazard harmfulness, the amount of physical exposure the hazard-bearing entities face, the sensitivity to the hazard, and the capacity to respond to the disaster. The analysis indicates that： （1） areas at high-risk of snow disaster on the Qinghai-Tibet Plateau are located in certain areas of the counties of Yecheng and Pishan in the Xinjiang region; （2） areas at medium-risk of snow disaster are found between the Gangdise Mountains and the Himalayas in the central-western part of the Qinghai-Tibet Plateau, and the southeastern part of the southern Qinghai Plateau; （3） the risk of snow disaster is generally low throughout the large area to the south of 30°N and the re- gion on the border of the eastern Qinghai-Tibet Plateau. Overall, the risk of snow disaster in high-altitude areas of the central Qinghai-Tibet Plateau is higher than that at the edge of the plateau.

Monitoring the 2008 cold surge and frozen disasters snowstorm in South China based on regional ATOVS data assimilation

In January 2008, South China experienced extremely low temperatures, heavy snowstorms, and severe frosts (2008 Frost Disaster, for short), which led to (partial) failures of observations from ground stations and ground radars resulting in a lack of necessary emergency information. To compensate for the failure of ground observations and to provide timely disaster information, the National Satellite Meteorological Center of China (NSMC) established a snow storm monitoring system for the 2008 Frost Disaster, which was based on the WRF Three Dimension Variational Assimilation and Forecast system (with NOAH as the land surface sub-process model) cooperatively developed by NSMC and the National Center for Atmospheric Research (NCAR), US. This system made full use of ATOVS and NCEP data to provide estimates of snow water equivalent every 6 hours during the storm. In this study, the ATOVS assimilation based snowstorm monitoring scheme was explored in detail, while the modeled results with and without ATOVS assimilation were compared against related observations. Results showed that the coupling of ATOVS assimilation into the proposed monitoring system evidently delineates weather characteristics of the snowstorm process more accurately, and demonstrated the feasibility of the system for snowstorm monitoring and forecasting. Through theoretical analyses and case discussion, this study proposes a reliable and practicable scheme to provide timely and accurate information on snow spatial distribution and temporal development for disaster mitigation, and illustrates a new application of ATOVS data.

基于多源数据的三江源区雪灾风险评估

三江源区是青海省雪灾最为严重的地区,对畜牧业影响较大。利用1961—2020年逐日积雪深度气象资料分析了三江源区冬季雪灾时空分布特征,运用MOD10A1积雪遥感数据提取积雪覆盖天数,选择最低气温、雪灾强度及积雪覆盖天数作为致灾因子,高程和坡向作为孕灾环境,地均人口、牲畜存栏及土地利用类型作为承灾体,构建雪灾风险评估模型,并评估三江源区冬季雪灾风险。结果表明:三江源区冬季雪灾呈增加趋势,称多地区最为严重,进入21世纪后雪灾极端性明显加剧;称多、玛多等地因最低气温低、雪灾强度大及积雪覆盖天数多导致致灾因子危险性最高,孕灾环境敏感性自东向西增强,人口及牲畜存栏均在东部地区较多,而草地在中、东部地区广泛分布,因此三江源区以中等承灾体脆弱区为主;基于所选因子建立三江源区冬季雪灾风险评估模型,并进行雪灾风险评估,三江源区中部称多、达日、甘德、同德、泽库及玛沁西部为雪灾风险较高的地区。

Indications of stratospheric anomalies in the freezing rain and snow disaster in South China,2008

NCEP/NCAR reanalysis data were used to characterize stratospheric temperature and water-vapor anomalies before and after the freezing rain and snow disaster of South China in 2008,and the influence of stratospheric circulation anomalies on the troposphere.Stratospheric temperature and water-vapor anomalies provided good leading indicators of this weather event.The period from December 1st 2007 to February 28th 2008 was divided into 18 pentads.During the 6th pentad,temperature decreased significantly at 10 hPa in the near-polar stratospheric region,and the decreasing trend strengthened and extended downward and southward to middle and lower latitudes.During the 14th-18th pentads,the temperature decrease reached its maximum and extended to 30°N.This coincided with the widespread freezing rain and snow event.By the end of January 2008,the temperature decrease ended in the near-polar stratospheric region,but continued in the mid-latitude area of the troposphere as the freezing rain and snow weather persisted.Similar to the temperature variations,positive anomalies of relative humidity in the stratospheric near-polar region also strengthened and extended downward and southward,coinciding with the freezing rain and snow event.Along with the significant relationship between the freezing rain and snow disaster and stratospheric circulation anomalies,the stratospheric polar vortex changed its shape in late December,intensifying and spreading downward from the top of the stratosphere and southward to the Asian continent,resulting in a deepening of the East Asian Trough and a strengthening of meridional circulation.Before the occurrence of the freezing rain and snow event,temperature and vapor increases in the stratosphere transferred downward to the troposphere,along with a stratospheric flow in the near-polar region southward to lower latitudes.

The Large Scale Circulation of the Snow Disaster in Southern China in the Beginning of 2008

This study analyzed the heaviest snowfalls or icy-rainfalls occurring in southern China from January to the beginning of February 2008.The results are summarized as follows：the disaster was induced by the persistent front of warm/cold air masses in southern China,which displayed an interaction between the weather systems in higher and lower latitudes.There was an adjustment for circulation at hemisphere scale during mid January by a variation of sign of the Arctic Oscillation（AO）index from negative to positive.The long lasting precipitation well coincided with a blocking situation centered near 80°E from mid January to the beginning of February.A diagnostic analysis indicates that stationary waves with an energy dispersion accompanying the blocking high propagated from upstream region in high latitudes to the south of the Yangtze River,which formed a maintaining energy source for the cyclonic circulation in situ.This resulted in that the large mass of cold air in high latitudes could not easily invade into the south but slowly shifted southward.On the other hand,the sea surface temperature（SST）over the warm pool of the western Pacific increased with a new history record due to the effect of the strong La Nina episode,which also blocked the cold air mass from the north.The blocking high collapsed around 30 January and the energy source for the local cyclonic circulation was cut off.Thus,the precipitation in southern China ceased after 1 February.

地形因子对森林林木冰雪灾害的影响

采用人机结合方法对广东省乳阳林场2022年初发生森林冰雪灾害的区域进行调查,运用奥维互动地图软件结合地形图、坡度仪等记录样地的海拔、坡向、坡位、坡度等地形因子,分析了这些地形因子对森林林木冰雪灾害的影响。结果表明,森林冰雪灾害与地形因子关系紧密,在一定范围内林木受损程度先随海拔升高而加重,超过一定海拔后随海拔升高而减弱;灾害等级越高越趋向于发生在阴坡或半阴坡;灾害级别越高坡位独特性越明显;坡度大小对林木受损程度影响明显,坡度越大、灾害等级越高。