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<br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />, <br />t <br />, <br /> <br />where Yo is the target area average observed precipitation (inches) and Yc is the target area. <br />average calculated precipitation (inches). The seeding effect can also be expressed as a percent <br />excess (or deficit) of the expected precipitation in the fonn: <br /> <br />SE ~ 100. (Yo - Yel/Ye <br /> <br />(4) <br /> <br />From equation (3) the ratio of the average December. March observed precipitation to <br />the average calculated precipitation in the target area was 1.03 or from (4), 3 percent more than <br />what was predicted from the average precipitation that was observed to fall in the control area <br />gages. <br /> <br />Similarly. the most probable average target area precipitation was calculated to be 6.23 <br />inches for the target sites excluding McClure Pass. from equation (2). The actual observed <br />average precipitation for the seven gages in the target group was 6.49 inches, again, higher than <br />that predicted. <br /> <br />From equation (3) the ratio of the average February - March observed precipitation to the <br />average calculated precipitation in the target area was 1.04 or from (4). 4 percent more than \,,'hat <br />was predicted from the control area precipitation. <br /> <br />The results using precipitation gage data. from regression equations both including and <br />excluding McClure Pass (near the northwest boundary of the target area). suggest some seeding <br />effects on December through ~1arch precipitation observations in the target area. Historical <br />seeding projects in the area (such as the Grand ~1esa program) may mask thc effects of seeding <br />in Gunnison County since many of the historical seasons used to devclop the regression <br />equations were seeded in the Grand ~1esa and West Elks program. In other words, the actual <br />results of seeding may "ell be higher than the current indications since it is expected that <br />the two adjacent seeding programs "ould ha,'e increased the precipitation in the Gunnison <br />targer areas during the historical period that \\t' used to establish our linear regression <br />equations. In order to illustrate this point. the historical data for the target stations were reduced <br />by 5%, each season to approximate the possible dO\\TIwind effects of seeding from the Grand <br /> <br />41 <br />