Observation and analysis of the urban heat island effect on soil in Nanjing, China

The heat island effect in urban meteorology has received significant attention in the recent years. In order to investigate the heat island effect on urban soil, two observation stations were built, respectively, in an urban area and a rural area of Nanjing city, China. The temperatures of underground soil (0?C300?cm depth) were recorded continuously for 1?year from June 2009 to June 2010. The data show that the urban soil temperature is generally higher than the rural soil temperature, and reveal an obvious heat island effect in urban soil with average intensity of 2.02°C over the 1-year period. The intensity varies between days, months and seasons: the daily urban heat island intensity (UHII) of soil ranges from 0.37°C to 3.98°C; the monthly UHII of soil ranges from 1.34°C (November) to 3.05°C (July); the order of seasonal UHII is summer (2.45°C)?>?winter (2.03°C)?>?spring (1.63°C)?>?autumn (1.53°C). The temperature data indicate that the maximum influence depth of daily synoptic events on the subsurface temperature is approximately 60?cm; the UHII generally increases with increasing depth. In addition to soil temperature, the temporal?Cspatial variation of soil moisture in a 100?cm profile depth was also investigated in this study. It is found that the moisture content of urban soil is generally lower than that of rural soil, which reveals an obvious dry island effect with average intensity of ?7.2% over the 1-year period; the maximum single-day urban dry island intensity (UDII) in soil is ?28.0%; the maximum average monthly UDII is ?19.1%, observed in July; the seasonal UDII shows a tendency of summer (?13.8%)?>?spring (?6.3%)?>?autumn (?5.2%)?>?winter (?3.7%). In profile, soil moisture content generally increases with increasing depth, and the maximum UDII is ?25.8% at 40?cm depth. In addition, the large-scale measurement results of 600 general points also confirm that the heat island and dry island effects are exist in urban soil.     

Evaluation of urban heat island effect in Turkey

Recently, the rate of urbanisation has accelerated due to increasing population density which causes unexpected environmental disturbances and problems. One of the major problems encountered to date is the change in the land use/cover (LULC) structure. Increasing the impervious surface cover has changed microclimatic properties of urbanised areas by altering their thermal characteristics. One of the most important problems facing urban planning today is the phenomena known as the urban heat island (UHI), which is largely due to the changing the character of LULC. In this study, to create a national picture of the UHI structure in Turkey, seven cities, namely Istanbul, Bursa, Ankara, Izmir, Gaziantep, Erzurum and Trabzon, each located in different climatic regions of Turkey, were investigated. The Gaussian fitting technique was applied to characterise the UHI effect in the seven cities in the study. An original contribution of the current study was that the rural reference temperature surface was automatically determined by a proposed algorithm including the automatic masking of input data, as well as the application of iterative Gaussian low-pass filtering during the fitting procedure. Within this context, the daytime and nighttime surface urban heat island (SUHI) effect was modelled and temporally analysed from 1984 to 2011 for all the sub-regions using remote sensing techniques. Furthermore, atmospheric UHI was also investigated using the mobile transect method. The findings from this study suggest that UHI is a major environmental problem in urbanised areas, both atmospheric UHI and SUHI were detected in all cities in the study area, and this problem was found to have rapidly increased from 1984 to 2011. Finally, as inferred from the multiple regression results, it can be concluded that the UHI problem in Turkey might have resulted from the altered LULC structure, as well as anthropogenic pressure on and interference in city planning geometries.     

High resolution aerosol data from MODIS satellite for urban air quality studies

The Moderate Resolution Imaging Spectroradiometer (MODIS) provides daily global coverage, but the 10 km resolution of its aerosol optical depth (AOD) product is not suitable for studying spatial variability of aerosols in urban areas. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for MODIS which provides AOD at 1 km resolution. Using MAIAC data, the relationship between MAIAC AOD and PM_2.5 as measured by the 27 EPA ground monitoring stations was investigated. These results were also compared to conventional MODIS 10 km AOD retrievals (MOD04) for the same days and locations. The coefficients of determination for MOD04 and for MAIAC are R² =0.45 and 0.50 respectively, suggested that AOD is a reasonably good proxy for PM_2.5 ground concentrations. Finally, we studied the relationship between PM_2.5 and AOD at the intra-urban scale (?10 km) in Boston. The fine resolution results indicated spatial variability in particle concentration at a sub-10 kilometer scale. A local analysis for the Boston area showed that the AOD-PM_2.5 relationship does not depend on relative humidity and air temperatures below ～7 °C. The correlation improves for temperatures above 7–16 °C. We found no dependence on the boundary layer height except when the former was in the range 250–500 m. Finally, we apply a mixed effects model approach to MAIAC aerosol optical depth (AOD) retrievals from MODIS to predict PM_2.5 concentrations within the greater Boston area. With this approach we can control for the inherent day-to-day variability in the AOD-PM_2.5 relationship, which depends on time-varying parameters such as particle optical properties, vertical and diurnal concentration profiles and ground surface reflectance. Our results show that the model-predicted PM_2.5 mass concentrations are highly correlated with the actual observations (out-of-sample R² of 0.86). Therefore, adjustment for the daily variability in the AOD-PM_2.5 relationship provides a means for obtaining spatially-resolved PM_2.5 concentrations.     

Local warming of groundwaters caused by the urban heat island effect in Istanbul, Turkey

The urban heat island (UHI) is a result of urbanization, causing local microclimatologic changes such as increase in ambient temperature. Factors causing the UHI effect are anthropogenic energy release, energy absorption by concrete, tarmac structures and traffic, although the main factor is the replacement of vegetation with man-made structures. These factors cause heating of not only local air but also subsurface and groundwater. Observations of groundwater temperatures from the urban, southern part of Istanbul (Turkey) and the rural, northern part of Istanbul revealed that the urban groundwater temperatures were 3.5°C higher than the rural. Urbanization is a direct consequence of improvements in technology and modern life. However, this comes at the cost of an ever-increasing demand for energy. Exploitation of low-enthalpy geothermal energy is an attractive alternative to fossil fuel based energies. From the environmental point of view, clean and cheap energy is the most preferable, with heat pumps being the best choice for recovery purposes. Usage of elevated groundwater temperature in the heat pumps in urban areas increases the efficiency of the heat pump system and yields more thermal energy than that of rural groundwater. This system may be applicable to Istanbul.     

Monitoring large oil slick dynamics with moderate resolution multispectral satellite data

Accidental release of crude oil into the sea due to human activity causes water pollution and heavy damages to natural ecosystems killing birds, fish, mammals and other organisms. A number of monitoring systems are used for tracking the spills and their effects on the marine environment, as well as for collecting data for feeding models. Among them, Earth observation technologies play a crucial role and moderate spatial resolution satellite systems are able to collect images with a very short revisit time or even daily. This paper describes the use of Moderate-Resolution Imaging Spectroradiometer data for monitoring large oil slicks with the fluorescence/emissivity index and object-based image analysis. Two case studies are presented: the Deepwater Horizon (2010) and the Campos Basin (2011) oil spill accidents. Results show that it is possible to track the dynamics of the slick both for massive and long-lasting accidents and for smaller and very quick accidents. The main advantages of the method proposed are a straightforward implementation, a fast and semi-automated data processing and the capability of integration of daytime and nighttime acquisitions, as well as its adaptability to different sensors.     

Estimation of surface latent heat fluxes from IRS-P4/MSMR satellite data

The brightness temperatures of the Microwave sensor MSMR (Multichannel Scanning Microwave Radiometer) launched in May 1999 onboard Indian Oceansat-1 IRS-P4 are used to develop a direct retrieval method for latent heat flux by multivariate regression technique. The MSMR measures the microwave radiances at 8 channels at frequencies of 6.6, 10.7, 18 and 21 GHz at both vertical and horizontal polarizations. It is found that the surface LHF (Latent Heat Flux) is sensitive to all the channels. The coefficients were derived using the National Centre for Environmental Prediction (NCEP) reanalysis data of three months: July, September, November of 1999. The NCEP daily analyzed latent heat fluxes and brightness temperatures observed by MSMR were used to derive the coefficients. Validity of the derived coefficients was checked within situ observations over the Indian Ocean and with NCEP analyzed LHF for global points. The LHF derived directly from the MSMR brightness temperature (Tb) yielded an accuracy of 35 watt/m². LHF was also computed by applying bulk formula using the geophysical parameters extracted from MSMR. In this case the errors were higher apparently due to the errors involved in derivation of the geophysical parameters.     

Characterization of the subsurface urban heat island and its sources in the Milan city area,Italy

Urban areas are major contributors to the alteration of the local atmospheric and groundwater environment. The impact of such changes on the groundwater thermal regime is documented worldwide by elevated groundwater temperature in city centers with respect to the surrounding rural areas. This study investigates the subsurface urban heat island (SUHI) in the aquifers beneath the Milan city area in northern Italy, and assesses the natural and anthropogenic controls on groundwater temperatures within the urban area by analyzing groundwater head and temperature records acquired in the 2016–2020 period. This analysis demonstrates the occurrence of a SUHI with up to 3 °C intensity and reveals a correlation between the density of building/subsurface infrastructures and the mean annual groundwater temperature. Vertical heat fluxes to the aquifer are strongly related to the depth of the groundwater and the density of surface structures and infrastructures. The heat accumulation in the subsurface is reflected by a constant groundwater warming trend between +0.1 and?+?0.4 °C/year that leads to a gain of 25 MJ/m² of thermal energy per year in the shallow aquifer inside the SUHI area. Future monitoring of groundwater temperatures, combined with numerical modeling of coupled groundwater flow and heat transport, will be essential to reveal what this trend is controlled by and to make predictions on the lateral and vertical extent of the groundwater SUHI in the study area.

     

Quantifying the response of surface urban heat island to urbanization using the annual temperature cycle model

Urban heat island(UHI),driving by urbanization,plays an important role in urban sustainability under climate change.However,the quantification of UHI’s response to urbanization is still challenging due to the lack of robust and continuous temperature and urbanization datasets and reliable quantification methods.This study proposed a framework to quantify the response of surface UHI(SUHI)to urban expansion using the annual temperate cycle model.We built a continuous annual SUHI series at the buffer level from 2003 to 2018 in the Jing-Jin-Ji region of China using MODIS land surface temperature and imperviousness derived from Landsat.We then investigated the spatiotemporal dynamic of SUHI under urban expansion and examined the underlying mechanism.Spatially,the largest SUHI interannual variations occurred in suburban areas compared to the urban center and rural areas.Temporally,the increase in SUHI under urban expansion was more significant in daytime compare to nighttime.We found that the seasonal variation of SUHI was largely affected by the seasonal variations of vegetation in rural areas and the interannual variation was mainly attributed to urban expansion in urban areas.Additionally,urban greening led to the decrease in summer daytime SHUI in central urban areas.These findings deepen the understanding of the long-term spatiotemporal dynamic of UHI and the quantitative relationship between UHI and urban expansion,providing a scientific basis for prediction and mitigation of UHI.     

Magnetic evidence of anthropogenic dust deposition in urban soils of Shanghai,China

The magnetic particulates from anthropogenic activities can be detected by magnetic methods rapidly and cost-effectively. This study focused on the investigation of vertical variations in magnetic properties in soil profiles and magnetic enhancement originating in Baoshan, Shanghai. Also the feasibility of using arable and urban park soils as a new context for magnetic monitoring was explored. A combination of magnetic and scanning electron microscopic (SEM) techniques was applied to three soil profiles. Non-pedogenic magnetic enhancement in topsoil was recorded at all three sites accompanied by coarsening of magnetic grain size. The dominant magnetic properties reflect multi-domain (MD) and pseudo-stable single domain (PSD) ferrimagnetic minerals. Both of magnetic concentrations and grain size decrease with the depth, depending on the pollutant input, soil type and degree of vertical mixing. SEM images confirmed the presence of anthropogenic particulates fly-ash. It was concluded from this study that topsoil magnetic enhancement arising from atmospheric contaminants was readily identifiable in both arable fields and urban parks, thus broadening the scope of magnetic research on urban and industrial pollution.     

Monitoring of hazards and urban growth in Villavicencio, Colombia, using scanned air photos and satellite imagery

A method is presented to monitor the development of geomorphic hazard areas by overlaying time series of air photos in a digital image processing system. The present study deals with such hazards affecting an urban area, Villavicencio at the foot of the eastern Andes in Colombia. The relevant windows of the air photos are digitized by flat-bed scanning and then transformed geometrically to be overlain on SPOT panchromatic imagery where available. The 10 m resolution of the satellite imagery allows, in practice, sufficient detail to bring out the differences, which are a yardstick to monitor the development of the phenomenon over time. Where no SPOT panchromatic imagery is available, one of the photos may be taken as a reference; registration to a topographic base map is also possible. A development over time to the present hazardous situations can be read from the analyzed imagery. Air photo series dating back to 1937 are available for this research, in the context of a geomorphic hazards study currently undertaken in the eastern Colombian Andes front where it pushes against the Llanos Orientales. The mountain front is quite steep and high, and the contact with the plains is very abrupt. A thrust fault zone in which the rocks are strongly mylonitized, marks the eastern front. Villavicencio lies just below this zone, but its main access road has to cross it. The terrain is mostly made up of Mesozoic and Palaeozoic sedimentary series, with prominent black lutites; Tertiary sedimentaries are found in the foreland. All rocks are strongly folded and faulted. Precipitation is in the order of 3500–5500 mm per year. Records on river discharge events are scarce or absent. Seismic events are frequent in the area. This area is prone to strong and rapid geomorphic processes posing hazards to the inhabitants. The town of Villavicencio is the gateway to the Llanos Orientales. It is the major town for hundreds of kilometres around, and a commercial, educational and health centre for the whole eastern region of Colombia. It is connected to Santa Fe de Bogotá, the national Capital, by the only highway to the Llanos, which traverses very difficult terrain through the Eastern Andes, and is cut frequently by landslides, bridge collapse etc., as a result of the torrential rainfall and the instability of the terrain. A major hazard is a big landslip known as the Mirador, close to Villavicencio, on the main road to Bogotá. Its rapid advancement has caused numerous road closures; its growth could be monitored on the scanned and registered air photos. The shifting and flooding of the Guatiquía River threatens the left bank, on which the airport of Villavicencio is situated. The development of the flood hazard, and the areal extent of the area threatened, is monitored and measured on the scanned and referenced air photos. The areal growth of the town of Villavicencio itself could likewise be monitored and measured. This revised version was published online in July 2006 with corrections to the Cover Date.     

2010上海世博会上欧泊营销的启示

欧泊是一种具有特殊光学效应的宝石,其变幻莫测的色彩令人着迷。但在国内珠宝市场上欧泊的销售份额很小,有关其有效营销方法研究方面的参考资料基本处于空白状态。借助2010年上海世博会的契机,结合笔者在澳大利亚馆销售欧泊产品4个月的经历,着重从多角度吸引顾客、留住顾客、销售攻心术、灵活引导及创新推广活动等方面分析了澳大利亚AODC公司的营销策略,从中总结出几点建议,旨在对国内珠宝营销有所启发。     

Monitoring Muztagh Kuksai glacier surface velocity with L-band SAR data in southwestern Xinjiang, China

This study presents the results of measuring surface velocity fields of alpine glaciers with multi-temporal ALOS/PALSAR synthetic aperture radar (SAR) data using the normalized cross-correlation technique. The main limitations of spaceborne optical data and interferometric SAR for retrieving reliable interferometric product are firstly discussed. Next, an efficient method of deriving surface velocity with spaceborne SAR system using the intensity-tracking method based on the cross-correlation optimization is expounded. This method is an invaluable alternative way of estimating the glacier surface field when the differential SAR interferometry is limited by the loss of coherence and can also overcome the drawback of the lack of available optical data in alpine glacier areas. The method was successfully applied in the region of the Muztagh Kuksai Glacier using ALOS/PALSAR L-band data with 44 days temporal separation. The glacier surface velocity fields were obtained for two different time intervals (14 January to 11 March 2009 and 1 September to 17 October 2009). The accuracy of the method was estimated from the residual value in the non-glacier area, which is often used to evaluate the performance of the approach for monitoring the glacier surface velocity. Finally the distribution maps of the surface velocity fields on the Muztagh Kuksai Glacier were retrieved with an accuracy of 0.3 m (SD 0.2 m) using L-band spaceborne SAR data. The results show that overall average velocity for 1 September to 17 October in 2009 is about 11 % faster than that for 14 January to 11 March in 2009. It is concluded that the potential of monitoring the long-term evolution of glaciers with SAR data should be emphasized.     

Monitoring of the urban sprawl using geoprocessing tools in the Shenzhen Municipality,China

Shenzhen, located in South China has experienced rapid urbanization over the past three decades. This paper focuses on the urban sprawl integrating remote sensing and geographic information systems (GIS). The overlay of the urban area maps for two adjacent study years was used to generate the sprawl categories map. The three main sprawl categories of infilling sprawl, edge-expansion sprawl and outlying sprawl were calculated and analyzed in regard to their distribution and change throughout different counties during the study years. The result showed that the urban area in the study region had increased dramatically from 19.55 km² in 1979 to 894.31 km² in 2005. The urban area centroids over the six study years transferred from southwest to northeast from 1979 to 2005. Among the study counties, the patterns of sprawl categories were markedly distinctive over different study periods. From 1979 to 2005, Shenzhen’s chief spread was outlying sprawl. Bao’an experienced the maximum sprawl within the three study counties. The findings show that studying urban sprawl can provide a method of monitoring urban area change, which, in turn, gives us a clearer perspective of urban sprawl patterns over a longer period of time. This would prove invaluable to those researchers such as land and urban planners.     

中国南海卫星重力数据Butterworth滤波处理

通过对重力模型数据进行Butterworth滤波处理,发现该方法对高频噪声具有很好的滤波效果。对Geosat和ERS—1卫星提供的重力数据进行了网格化和Butterworth滤波处理,得到中国南海自由空气重力异常值为-42~89 m Gal。经与GRACE卫星提供的数据进行比较,发现该方法得到的结果具有更好的精度和分辨率。     

Monitoring groundwater changes in the Yangtze River basin using satellite and model data

Space-borne geodetic sensors and model-based datasets have been used to monitor groundwater changes in the Yangtze River basin (YRB). Groundwater storage variations were computed using the following datasets:? Gravity Recovery and Climate Experiment (GRACE)-derived terrestrial water storage (TWS),? Noah driven Global Land Data Assimilation System (GLDAS-Noah) model to simulate the total water content (TWC) i.e. soil moisture, ice and snow, and canopy water storage, and? Satellite altimetry-observed surface water reservoir storages.Overall, the results show that groundwater in the YRB rose by at least 3.34 km³/yr between January 2003 and December 2009. However, the estimated groundwater linear trend for the period of 2003–2009 was ?0.95 km³/yr according to the Changjiang and Southwest Rivers Water Resource Bulletin (CJSRWB). An analysis of the methodology of the CJSRWB shows that the groundwater estimate was based on the water balance approach, which has been found to be weak in inter-basin sub-surface flow. The GRACE-estimated groundwater rise is larger and suggests that the YRB is affected by seepage from Tibetan lakes through a sub-surface fault. Additionally, there is evidence showing that water loss from the Yangtze River by underground leakage through faults could also be a cause of the difference. Therefore, it is concluded that further investigation is required to determine the causation.     

Understanding land surface temperature on rift areas to examine the spatial variation of urban heat island: the case of Hawassa,southern Ethiopia

GeoJournal - Examining the spatial variation of surface temperature is an important criterion to create livable urban environment. To examine the cause of heat island variation in the study area...     

Soil temperatures in four metropolitan cities of Korea from 1960 to 2010: implications for climate change and urban heat

This study was conducted to reveal the trends of the air temperature and soil temperature for 51 years (1960–2010) and their relationship in four of Korea’s largest metropolitan cities (Seoul, Incheon, Busan and Daejeon). Also, the trends of the air and soil temperatures between the studied metropolitan cities and a rural area (Chupungryong) were compared to examine the effect of urban heat. Among the metropolitan cities, the long-term mean soil temperatures (depth 0.0, 0.5, 1.0, 1.5, 3.0, 5.0 m) were lowest (13.34–14.80 °C) in Seoul and highest (16.24–16.54 °C) in Busan, which is mainly the effect of the latitude. The soil temperature exponentially increased with depth in the three cities except for Busan and was closely related to the air temperature. The soil temperatures responded well to the air temperature change (maximum correlation coefficients 0.88–0.98) but this response was slightly delayed with depth. The air and soil temperatures increased at the rates of 0.24–0.40 and 0.11–0.73 °C/decade, respectively, for the period. The increasing rate of the soil temperature was the largest in Daejeon as 0.39–0.73 °C/decade, which was almost 2–4 times greater than those of the other cities (0.11–0.40 °C/decade), and it rose with depth. The increase of the soil temperature was coincident with the increase of the air temperature, which indicates that the soil temperature was largely affected by the increasing of the air temperature. In contrast, the increase in air temperature in Chupungryong (0.06 °C/decade) was significantly lower than in the metropolitan cities. In addition, the increase of the soil temperature in the rural area (0.13 °C/decade) was also much lower than that in the inland cities (0.20–0.27 °C/decade) while it showed no substantial difference from that in the coastal cities (0.11–0.15 °C/decade). Therefore, it is inferred that the soil temperature of the metropolitan cities increased with the increase of the air temperature due to global warming as well as the anthropogenic urban heat.     

Water quality evolvement from Huangpu River, Shanghai, China

The Huangpu River supplies eighty percent of daily water used for life and industry for about 20 million people in Shanghai, China. Industry and domestic sewerage from the metropolis is mainly released into the Huangpu River, which flows through the Shanghai City area. The pollution caused by city life and production in the Huangpu River has occurred for years. In this paper, the contents of heavy metals （Cu, Pb, Cr, Cd, and Hg）, total organic carbon （TOC）, and polynuclear aromatic hydrocarbons （PAHs） in the Huangpu River are studied. Data from environmental monitoring from 1991 to 2002 are compared to understand the variation and trends of the pollution. Results indicate that metals have been reduced efficiently, but organic pollutants develop in an aggravating trend as domestic sewage increases. The variation of the organic pollutant concentrations, which are lower than those of other similar rivers of China, US, and Canada,     

Monitoring of Dead Sea water surface variation using multi-temporal satellite data and GIS

Remote sensing (RS) and geographic information systems (GIS) are very useful for environmental-related studies, particularly in the field of surface water studies such as monitoring of lakes. The Dead Sea is exposed to very high evaporating process with considerable scarcity of water sources, thus leading to a remarkable shrinkage in its water surface area. The lake suffers from dry out due to the negative balance of water cycle during the previous four decades. This paper discusses the application of RS, GIS, and Global Positioning System to estimate the lowering and the shrinkage of Dead Sea water surface over the period 1810–2005. A set of multi-temporal remote sensing images were collected and processed to show the lakes aerial extend shrinkage from 1973 up to 2004. Remote sensing data were used to extract spatial information and to compute the surface areas for Dead Sea for various years. The current study aims at estimating the fluctuation of Dead Sea level over the study period with special emphasis on the environmental impact assessment that includes the degradation level of the Dead Sea. The results indicated that there is a decrease of 20 m in the level of the Dead Sea that has occurred during the study period. Further, the results showed that the water surface area of the Dead Sea has shrunk from 934.26 km² in 1973 to 640.62 km² in 2004.