A field-based index of topographic shelter and its application to topoclimatic variation

Topographic and local shelter are important determinants of spatial variation within environmental systems,particularly in upland areas. A numerical index of shelter is developed based on in situ measurements of horizon declination or inclination, which can be modified to incorporate the directional frequency of airflow at a site, Reference is made to a case study of the application of the index to an isolated hill in Cleveland, in northern England. Temperature and vapour pressure are found to be determined primarily by altitude, while the Incorporation of shelter index values improves the prediction of windspeeds. This has potential applications in a range of environmental processes.