Geostatistical exploration of spatial variation of summertime temperatures in the Detroit metropolitan region

Background

Because of the warming climate urban temperature patterns have been receiving increased attention. Temperature within urban areas can vary depending on land cover, meteorological and other factors. High resolution satellite data can be used to understand this intra-urban variability, although they have been primarily studied to characterize urban heat islands at a larger spatial scale.

Objective

This study examined whether satellite-derived impervious surface and meteorological conditions from multiple sites can improve characterization of spatial variability of temperature within an urban area.

Methods

Temperature was measured at 17 outdoor sites throughout the Detroit metropolitan area during the summer of 2008. Kriging and linear regression were applied to daily temperatures and secondary information, including impervious surface and distance-to-water. Performance of models in predicting measured temperatures was evaluated by cross-validation. Variograms derived from several scenarios were compared to determine whether high-resolution impervious surface information could capture fine-scale spatial structure of temperature in the study area.

Results

Temperatures measured at the sites were significantly different from each other, and all kriging techniques generally performed better than the two linear regression models. Impervious surface values and distance-to-water generally improved predictions slightly. Restricting models to days with lake breezes and with less cloud cover also somewhat improved the predictions. In addition, incorporating high-resolution impervious surface information into cokriging or universal kriging enhanced the ability to characterize fine-scale spatial structure of temperature.

Conclusions

Meteorological and satellite-derived data can better characterize spatial variability in temperature across a metropolitan region. The data sources and methods we used can be applied in epidemiological studies and public health interventions to protect vulnerable populations from extreme heat events.     

中药塌渍防渗包的设计与应用

正中药塌渍是一种传统的中药外治方法,多用于治疗腰椎间盘突出症、颈椎病、风湿病、类风湿性关节炎等~([1])。中药塌渍治疗时,将药垫浸透药液,湿敷在治疗部位,通过红外灯照射,利用热力经皮透入吸收,达到治疗的效果。目前,临床上的药垫多采用柔绵材料(如:纱布等)制作,虽具有柔韧、亲肤、吸水量大等优点,但在塌渍治疗过程中,一方面药液会从药垫四周渗     

垃圾卫生填埋场防渗层的设计

针对垃圾卫生填埋场防渗层的设计，介绍了膨润土、高密度聚乙烯膜和一些新型防渗材料的种类和性质，及单层防渗层、复合防渗层的结构设计。