项目经济活动分析在城市副中心剧院工程的运用

随着建筑行业的飞速发展,建筑施工模式也伴随时代进步,延伸出新的工作方法来指导施工。以城市副中心剧院工程为例,项目经济活动分析在大型公共建筑中的具体运用,并分享施工过程中运用“项目经济活动分析”案例的相关经验。

冰川冰储量计算方法及发展趋势

冰川冰储量不仅是冰川的重要属性,而且是核算冰川水资源及预测冰川变化的基础数据,因此准确计算冰川冰储量及其变化具有重要的理论与现实意义。目前冰川储量估算的主要方法有经验公式法、冰厚模型估算法、探地雷达法;冰川储量相对变化计算方法有实地测量法和遥感监测法。通过系统分析和讨论各计算方法的原理、现状及存在的问题,以期为冰川储量估算提供方法参考。研究表明:对于冰川冰储量计算而言,经验公式法适用于区域性或全球性的冰川储量估算;模型估算法适用于个体或小范围冰川储量估算;探地雷达法适用于人类易到达区域冰川储量的估算。对于冰川冰储量相对变化计算,实地测量法适用于对精度要求高且满足实地测量条件的单条或中小型冰川,遥感监测法适用于全球性冰储量变化估算,但需改进算法和提高数据空间分辨率。目前,随着无人机技术的逐步应用,以及冰川流速等理论模型的提出,为冰川冰储量估算方法的发展提供了新契机。

Glacier change in the Tanggula Mountains, Tibetan Plateau,in 1969-2015

To improve our knowledge of glacier change in the Tanggula Mountains located in the northeast of the Tibetan Plateau,we delineated outlines of the glaciers in 1991 and 2015 using Landsat TM/OLI images and compared them with the reported glacier data in the First Chinese Glacier Inventory in 1969 and the Second Chinese Glacier Inventory in 2007.These comparisons showed that the glacier area and ice volume decreased by 524.8 km2 and 37 km3,respectively.The majority of the glacier area loss was concentrated in the area class of 1-5 km2,between 5300 m and 5500 m in elevation,on north and east facing slopes and in the Dam Qu River basin.These glacier changes exhibited spatial and temporal differences.The glacier retreat rate gradually increased from 1969 to 2015,and the rate in the east was higher than that in the west.From 1969 to 2015,the warming rate in the Tanggula Mountains was 0.38°C/10a,while the annual precipitation only increased by 0.4%.The slight increase in the amount of precipitation made a limited contribution to glacier change,while the change in temperature led to noticeable shrinkage of the glaciers.Contrary to the retreat or stagnation of most glaciers in the study area,there were 10 glaciers that experienced clear advance in 1986-2015 with noticeable increases in both area and length.Whether or not these 10 glaciers are surge glaciers requires further study.

Lake inventory and potentially dangerous glacial lakes in the Nyang Qu Basin of China between 1970 and 2016

There are a large number of glaciers and lakes developed in the Nyang Qu Basin of China. Recent climate change has significant impacted on the high-mountain glacial environment. Rapid melting of glaciers contributes to the formation and expansion of moraine-dammed lakes which increase the probability of glacial lake outburst floods(GLOFs). We calculated a multi-temporal lake inventory based on(1) topographic maps in the 1970 s,(2) satellite imageries from 1990 to 2016,(3) First Chinese Glacier Inventory(FCGI),(4) Glacier Inventory of Southeastern Tibet(GIST) and(5) meteorological data. A total of 880 lakes(>0.01 km^2) have been mapped in 2016, with 318 being glacial lakes(GLs) and 462 non-glacier lakes(NGLs). Most of the lakes were mainly located at 4500 m a.s.l. and the lakes dominated by small lakes(<0.1 km^2) where the change of their actual sizes are more significant compared to the larger ones. Meanwhile, we found that there were 178 newly formed GLs and 51 of them had disappeared between 1970 and 2016. During the same period, there can be identified 157 newly formed GLs and 226 had disappeared. We additionally performed a hazard and risk assessment for GL in 2016 and exposed 14 potentially dangerous morainedammed lakes(PDMDLs), covering a total area of 5.88 km2 in the Nyang Qu Basin. There can be found 4 GLs with very high risk, 3 GLs with high risk, 4 GLs with medium risk and 4 GLs with low risk of GLOFs susceptibility. The findings of this study can be used for the future policy of risk management and also be adapted for promoting water resources management.

2000—2010年祁连山冰川冰储量变化

监测区域尺度冰川变化,特别是冰川物质平衡变化,对系统认识冰川及水资源变化具有重要价值。基于校正后的SRTM数据与ASTER立体像对数据,利用大地测量法,对2000—2010年祁连山地区冰川冰储量变化进行应用研究,结果表明：（1）多源遥感DEM数据经过空间匹配误差和空间分辨率相关误差校正,整体误差较小,适合对大空间尺度的冰川体积变化和物质平衡进行估算研究。（2）2000—2010年祁连山冰川厚度平均减薄（5.68±2.76）m,平均冰川物质平衡为（-0.48±0.23）m w.e.·a-1,冰川储量变化（-1.59±0.72）Gt。（3）疏勒河流域（5Y44）是祁连山地区冰川平均物质平衡和冰储量变化最为明显的区域,平均物质平衡为（-0.80±0.27）m w.e.·a-1,冰川厚度平均减薄（9.42±3.21）m,冰川储量亏损（-4.08±1.39）Gt。而冰川物质平衡变化最小的地区为黑河流域（5Y42）,冰川平均物质平衡为（-0.05±0.21）m w.e.·a-1,冰川储量亏损最少地区为大通河流域（5J42）,冰川储量变化为（-0.12±0.08）Gt。（4）祁连山地区冰川储量变化呈现自西向东增加的趋势,而物质平衡呈现自西向东减少的趋势。气温升高依然是冰川变化的主要因素。

1973-2018年布喀达坂峰地区前进冰川遥感监测

冰川跃动是冰川动力不稳定性的表现,影响着全球约1%的冰川。基于1973-2018年208景Landsat MSS/TM/ETM+/OLI遥感影像,对布喀达坂峰地区不同时期前进冰川进行遥感识别。结果表明:(1)1973-2018年布喀达坂峰地区共有7条冰川发生过前进,其中冰川末端快速退缩型冰川有3条,冰川末端波动前进型和冰川末端稳定型冰川各有2条。莫诺马哈冰川和5Y542H0020冰川可能为跃动冰川,且前者正处于跃动阶。(2)近45年间布喀达坂峰地区7条冰川共出现过25次前进现象,各条冰川发生前进次数均多于(含)2次;前进冰川发生时间主要集中于2000s(7次)和1970s(6次)。该地区冰川在各月份均发生过前进现象,推断该地区前进冰川属斯瓦尔巴型。布喀达坂峰地区冰川前进无明显规律,大多数冰川两次前进时间间隔为10年左右。(3)布喀达坂峰地区冰川前进可能受热控和水控机理共同作用,单一的气候变化尚难以解释其变化机理。