2001—2018年基于MODIS遥感影像的青海湖湖冰物候变化特征分析及其影响因素

青海湖是青藏高原上最大的咸水湖,研究该区域冬季湖泊冻融时间的变化趋势及其与气候变化之间的关系,可以为预测未来气候对青海湖水情变化提供重要的见解。根据冰的亮度温度值高于水的亮度温度值这一差异,使用2001—2018年MODIS MOD02QKM数据产品和Landsat TM/ETM+遥感影像分别提取了青海湖开始冻结、完成冻结、开始消融和完成消融四个时间点的数据,综合分析青海湖湖冰物候特征变化,并结合气象数据,得出湖冰物候变化对气候的响应。结果表明：青海湖每年11月左右进入冰期,12月开始形成稳定的冰盖,次年3月或4月开始消融。湖冰覆盖时长和封冻期的变化趋势基本相同,整体上呈现出缩短的趋势,湖冰消融期整体上呈现出先缩短后增加的趋势;2001—2018年,平均首日冻结面积为8.15%,平均冻结速率为192.02 km²?d^?1,开始冻结和完成冻结的日期略有延迟,开始消融和完成消融的日期已经大大提前;冬季温度越高,青海湖湖冰封冻时间越短,日照时数越长湖冰覆盖时长越短,对于湖冰消融期来说,降水量越多湖冰消融速度越慢,平均风速越大湖冰消融速度越快。初步认为,气温是湖冰冻融的主要因素,预测未来1—2 a青海湖冬季气温仍会呈现上升趋势,湖冰封冻时长也会出现缩短趋势。     

深井冰冷冻系统

深井降温是深部矿产资源开采过程中的主要技术问题之一 ,讨论一种深井降温的新技术及方法冰冷冻系统     

Description and evaluation of a model of deposition velocities for routine estimates of air pollutant dry deposition over North America.: Part I: model development

This paper describes the development of a detailed dry deposition model for routine computation of dry deposition velocities of SO₂, O₃, HNO₃ and fine particle SO₄²⁻ across much of North America. Four different dry deposition/surface exchange sub-models have been combined with the current Canadian weather forecast model (Global Environmental Multiscale model) with a 3 h time resolution and a horizontal spatial resolution of 35 km. The present model uses the US Geological Survey North American Land Cover Characteristics data to obtain fourteen different land use and five seasonal categories. The four sub-models used are a multi-layer model for gaseous species over taller canopy land-use types, a big-leaf model for gaseous species over lower canopies (including bare soil and water) and for HNO₃ under all surface types and, two different models for SO₄²⁻, one for tall canopies and the other for short canopies. All necessary parameters for each sub-model, chemical species, land-use and seasonal categories have been selected from available data libraries or from the values reported in the literature. The purpose for developing this model (referred to as the Routine Deposition Model (RDM)), when coupled with air concentration data, is to provide estimates of seasonal dry deposition, which can be combined with wet deposition to produce total deposition estimates. Model theory is discussed in this paper and model sensitivity tests and results will be presented in a companion paper.     

Development and application of a GIS-based sediment budget model

Accelerated erosion and increased sediment yields resulting from changes in land use are a critical environmental problem. Resource managers and decision makers need spatially explicit tools to help them predict the changes in sediment production and delivery due to unpaved roads and other types of land disturbance. This is a particularly important issue in much of the Caribbean because of the rapid pace of development and potential damage to nearshore coral reef communities. The specific objectives of this study were to: (1) develop a GIS-based sediment budget model; (2) use the model to evaluate the effects of unpaved roads on sediment delivery rates in three watersheds on St. John in the US Virgin Islands; and (3) compare the predicted sediment yields to pre-existing data. The St. John Erosion Model (STJ-EROS) is an ArcInfo-based program that uses empirical sediment production functions and delivery ratios to quantify watershed-scale sediment yields. The program consists of six input routines and five routines to calculate sediment production and delivery. The input routines have interfaces that allow the user to adjust the key variables that control sediment production and delivery. The other five routines use pre-set erosion rate constants, user-defined variables, and values from nine data layers to calculate watershed-scale sediment yields from unpaved road travelways, road cutslopes, streambanks, treethrow, and undisturbed hillslopes. STJ-EROS was applied to three basins on St. John with varying levels of development. Predicted sediment yields under natural conditions ranged from 2 to 7Mgkm(-2)yr(-1), while yield rates for current conditions ranged from 8 to 46Mgkm(-2)yr(-1). Unpaved roads are estimated to be increasing sediment delivery rates by 3-6 times for Lameshur Bay, 5-9 times for Fish Bay, and 4-8 times for Cinnamon Bay. Predicted basin-scale sediment yields for both undisturbed and current conditions are within the range of measured sediment yields and bay sedimentation rates. The structure and user interfaces in STJ-EROS mean that the model can be readily adapted to other areas and used to assess the impact of unpaved roads and other land uses sediment production and delivery.     

Helping small businesses implement toxics use reduction techniques: dry cleaners, auto shops, and floor finishers assisted in creating safer and healthier work places

The Toxics Use Reduction Institute (TURI), Boston Public Health Commission (BPHC), and Vietnamese American Initiative for Development (Viet-AID) have worked with small business sectors to reduce their use of toxic chemicals. Three cases, described here, in dry cleaning, auto shops and floor finishing share common approaches for creating successful models of effective dissemination of toxics use reduction in small businesses. These include direct business support, peer-to-peer training and promotion of alternatives, and collaborations with stakeholders to achieve greener businesses. These results were achieved despite predictable barriers of lack of resources, suspicion of safer alternatives, and language and cultural barriers.     

SNOW AND ICE ALBEDO MEASURED WITH TWO TYPES OF PYRANOMETERS1

ABSTRACT: In order to obtain total short-wave albedos of snow and ice, both incident and reflected solar radiation were measured over a frozen lake surface using two different types of radiation measurement devices: a Kipp and Zonen thermopile pyranometer with a spectral sensitivity of 300 to 2800 nm and a LI-COR photovoltaic pyranometer with a spectral sensitivity of 400 to 1100 am. The spectral response of the LI-COR pyranometers limits its use as a short-wave radiation measurement device. Therefore, two equations were developed to adjust both the daily incident radiation data and the daily reflected radiation data measured by the LI-COR instrument to total short-wave radiation values, i.e., to the waveband of 300 to 2800 nm (visible to near-infrared spectrum). The LI-COR data were then adjusted, and a total short-wave adjusted albedo was calculated with a modeling efficiency of 0.97.     

EFFECT OF SIMULATED CLIMATE CHANGE ON SNOWMELT RUNOFF MODELING IN SELECTED BASINS1

ABSTRACT: The projected increase in the concentration of CO₂ and other greenhouse gases in the atmosphere is likely to result in a global temperature increase. This paper reports on the probable effects of a temperature increase and changes in transpiration on basin discharge in two different mountain snowmelt regions of the western United States. The hydrological effects of the climate changes are modeled with a relatively simple conceptual, semi-distributed snowmelt runoff model. Based on the model results, it may be concluded that increased air temperatures will result in a shift of snowmelt runoff to earlier in the snowmelt season. Furthermore, it is shown that it is very important to include the expected change in climate-related basin conditions resulting from the modeled temperature increase in the runoff simulation. The effect of adapting the model parameters to reflect the changed basin conditions resulted in a further shift of streamflow to April and an even more significant decrease of snowmelt runoff in June and July. If the air temperatures increase by approximately 5°C and precipitation and accumulated snow amounts remain about the same, runoff in April and May, averaged for the two basins, is expected to increase by 185 percent and 26 percent, respectively. The runoff in June and July will decrease by about 60 percent each month. Overall, the total seasonal runoff decreases by about 6 percent. If increased CO₂ concentrations further change basin conditions by reducing transpiration by the maximum amounts reported in the literature, then, combined with the 5°C temperature increase, the April, May, June, and July changes would average +230 percent, +40 percent, ?55 percent, and ?45 percent, respectively. The total seasonal runoff change would be +11 percent.     

APPLICATION OF THE SNOWMELT RUNOFF MODEL USING MULTIPLE-PARAMETER LANDSCAPE ZONES ON THE TOWANDA CREEK BASIN,PENNSYLVANIA1

ABSTRACT: The Snowmelt Runoff Model (SRM) is designed to compute daily stream discharge using satellite snow cover data for a basin divided into elevation zones. For the Towanda Creek basin, a Pennsylvania watershed with relatively little relief, analysis of snow cover images revealed that both elevation and land use affected snow accumulation and melt on the landscape. The distribution of slope and aspect on the watershed was also considered; however, these landscape features were not well correlated with the available snow cover data. SRM streamflow predictions for 1990, 1993 and 1994 snowmelt seasons for the Towanda Creek basin using a combination of elevation and land use zones yielded more precise streamflow estimates than the use of standard elevation zones alone. The use of multiple-parameter zones worked best in non-rain-on-snow conditions such as in 1990 and 1994 seasons where melt was primarily driven by differences in solar radiation. For seasons with major rain-on-snow events such as 1993, only modest improvements were shown since melt was dominated by rainfall energy inputs, condensation and sensible heat convection. Availability of GIS coverages containing satellite snow cover data and other landscape attributes should permit similar reformulation of multiple-parameter watershed zones and improved SRM streamflow predictions on other basins.     

MODEL ACCURACY IN SNOWMELT-RUNOFF FORECASTS EXTENDING FROM 1 TO 20 DAYS1

ABSTRACT: This paper examines the performance of snowmelt-runoff models in conditions approximating real-time forecast situations. These tests are one part of an intercomparison of models recently conducted by the World Meteorological Organization (WMO). Daily runoff from the Canadian snowmelt basin Illecille. waet (1155 km², 509–3150 m a.s.l.) was forecast for 1 to 20 days ahead. The performance of models was better than in a previous WMO project, which dealt with runoff simulations from historical data, for the following reasons: (1) conditions for models were more favorable than a real-time forecast situation because measured input data and not meteorological forecast inputs were distributed to the modelers; (2) the selected test basin was relatively easy to handle and familiar from the previous WMO project; and (3) all kinds of updating were allowed so that some models even improved their accuracy towards longer forecast times. Based on this experience, a more realistic follow-up project can be imagined which would include temperature forecasts and quantitative precipitation forecasts instead of measured data.     

船载雷达海冰监测及预报技术在辽东湾冰区油轮外输作业中的应用

渤海的辽东湾是世界上典型的海湾结冰区,位于冰区中的石油平台油轮外输作业中,流冰连续不断地漂移、聚集形成堆积冰,给海上油轮的外输作业安全带来严重危害。本文概述了在国内首次利用船载雷达,在该湾冰区石油平台上,现场采用雷达海冰监测预报技术系统,进行遥感海冰数据源的获取,图像的解译和数值化处理,得到流冰类型、冰厚度、流冰密集度、流冰速度、方向、流冰漂移轨迹等要素。同时首次现场实时计算出雷达冰漂流场矢量图,并开展了雷达海冰数值跟踪预报,在冰区油轮外输作业中得到很好应用,为雷达技术对水体和海冰监测和预报、遥感应用新领域提供科学依据。