Welcome to PRISM Help
PRISM Modification Window - This window allows you to modify the Mean Precipitation based on either annual precipitation or elevation. THis is a fine tuning tool that will allow you to find a more appropriate mean precipitation for your study area based on either the known annual precipitation or based on the elevation of the study site. To move around, click on any of the eight cells surrounding the current locations elevation/annual precipitation. Each move equal 2.5 minutes (approximately 2.5 miles). As the current position changes (the center cell), the monthly and annual mean precipitations will change on the left. Once you have determined the best values for your study site, click "Accept Values" to send these values to the Climate Modification Window (see previous). CLick "Return with no Changes" to ignore any changes and return to the previous window.