My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
WMOD00583
CWCB
>
Weather Modification
>
DayForward
>
WMOD00583
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/28/2009 2:41:09 PM
Creation date
4/24/2008 2:58:42 PM
Metadata
Fields
Template:
Weather Modification
Contract/Permit #
1-07-81-V0175
Title
Some Laboratory Tests of the Accuracy of the Belfort Universal Recording Raingage - Technical Report
Date
3/1/1985
Weather Modification - Doc Type
Report
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
43
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
Show annotations
View images
View plain text
<br />bias in reading the charts which might have resulted with <br />foreknowledge of the actual flow rates. A daily test period was <br />considered to commence with the beginning of the first control <br />period and conclude with the end of the last control period of <br />that day. The chart data were then plotted on the same graph as <br />the test flow data for comparison purposes. After all chart <br />readings were complete, the total catch within the raingage <br />beaker was weighed and plotted on the respective graph to compare <br />with the observed final chart level and with the final level <br />estimated from the control flow data. These plots appear in <br />Appendix A as Figures 4 to 18. During the test periods, air <br />temperatures recorded adjacent to the gages usually ranged <br />between 300 and 600 F. Most tests were conducted at temperatures <br />above freezing. <br /> <br />v. Results <br /> <br />Data collected from the testing program were reduced and <br />analyzed to determine the accuracy that can be obtained from the <br />gages. The effort was subdivided into four separate areas of <br />investigation to isolate and quantify potential sources of error, <br />and to determine accuracies possible at short- and long-time <br />scales. These results will be discussed below. <br /> <br />1. Chart reading accuracy. <br /> <br />A portion of the recorded data was independently <br />reduced by two analysts to determine the resolution and <br />accuracy obtainable during the manual data reduction process. <br />Both persons worked from photocopies of the original record <br />and made readings at identical times on charts. The results <br />indicated that the independent readings agreed to within <br />0.005 inch of each other over 95 percent of the time. Only <br />one case occurred where the difference was as much as 0.015 <br />inch. It must be noted, however, that the sample size was <br />small (22 points), there was no pressure to make the readings <br />quickly, and the analysts understood that their readings <br />would be compared. Thus, it is not realistic to expect <br />that routine reduction of large amounts of data would <br />achieve this level of accuracy. It is probable that chart <br />reading variations will introduce a ~ 0.01 inch or greater <br />error in the data under normal circumstances. <br /> <br />2. Gage chart fluctuations with no precipitation input. <br /> <br />Two tests were conducted to determine if fluctuations <br />in the chart record occurred during periods when no <br />precipitation was entering the gage. The tests were done by <br />operation of the chart drives over a period of approximately <br />20 hours while the gage buckets were completely empty except <br />for the metal calibration weight used to bring the pen trace <br />above the zero line on the chart. During the test period, <br />the temperature was relatively constant, ranging between 440 <br />and 500 F. <br /> <br />8 <br />
The URL can be used to link to this page
Your browser does not support the video tag.