Results From Experimental Rain‐Gages At Coshocton, Ohio

Abstract

Satisfactory shields and enclosures for the standard United States Weather Bureau type of rain‐and‐snow gage are essential to the accurate measurement of precipitation by gages placed in open areas. By using a limited number of widely distributed gages, it is usually possible to place them in properly sheltered sites. However, when the number and distribution‐density of the gages are increased, it is often extremely difficult to find suitable exposures. In connection with the watershed‐studies being conducted by the Soil Conservation Service of the United States Department of Agriculture near Coshocton, Ohio, where rain‐and‐snow gages are distributed at intervals of about one‐third mile over privately owned watersheds of several thousand acres area, many gages are necessarily exposed directly to wind‐action. In order that equipment may be developed for improving the catch of gages so exposed, an experimental plot has been established in the watershed‐area and equipped with several standard rain‐and‐snow gages on which various types of shields and enclosures are being tested.

Climate as a Determinant of Vegetation Distribution in Eastern Washington and Northern Idaho

“…But it is doubtful if such a simple approach will ever prove satisfactory because so much of the character of each climatic attribute has been sacrificed for the sake of brevity of expression. Many investigators have shown that unless rain gages are equipped with shields, such as the Alter or Nipher types, they do not accurately measure precipitation accompanied by a breeze, and a serious error is involved if precipitation is accompanied by strong wind, which is often the case (among others see Abbe 1893;Koschmeider 1934;Alter 1937;Riesbol 1938;Hoeck & Thams 1951;Helmers 1952). A third weakness of all classifications thus proposed is that a continuous series of values has been divided into a few groups.…”

“…One of these is that precipitation data are not collected in a manner that should be acceptable in science. Many investigators have shown that unless rain gages are equipped with shields, such as the Alter or Nipher types, they do not accurately measure precipitation accompanied by a breeze, and a serious error is involved if precipitation is accompanied by strong wind, which is often the case (among others see Abbe 1893;Koschmeider 1934;Alter 1937;Riesbol 1938;Hoeck & Thams 1951;Helmers 1952). In addition, where the topography is not flat, the gage and shield should both be tilted until the orifices are parallel with the land surface (Hamilton 1944;Helmers 1952).…”

Homogeneity adjustments ofin situ atmospheric climate data: a review

“…The existing U.S. cooperative rain gauge network measures rainfall with a bias of 3-10% and snowfall with a bias of up to 50% or more (Larson and Peck, 1974;Groisman and Legates, 1994). Over the last century, the U.S. has experienced a systematic increase of the mean angle from the gauge to nearby obstacles which can be explained by official instructions to place the gauge in more protected sites (Alter, 1937;Riesbol, 1938). Over time, this can cause an increase in measured winter precipitation that can result in significant spurious positive trends in frozen and liquid precipitation derived from the observed precipitation data even when there is no actual change in precipitation.…”

Reducing biases in estimates of precipitation over the United States: Phase 3 adjustments

“…Problems with the accuracy of precipitation measurements occur primarily for frozen precipitation and for liquid precipitation with an intensity less than 0.03 mm per minute [Riesbol, 1938[Riesbol, , 1940Larkin, 1947;Bogdanova, 1966;Sevruk, 1982;Larson and Peck, 1974;Folland 1988]. Therefore our main efforts have been to develop adjustment procedures for measurements of these two types of precipitation.…”

“…Such an assessment was made by Golubev [1991Golubev [ , 1993 for several gauges installed at the Valdai precipitation Occurrence of different types of rainfall and percent losses of measured liquid precipitation from a standard openly exposed unshielded rain gauge. For central Ohio, the empirical estimate of losses is from Coshocton, Ohio [Riesbol, 1938[Riesbol, , 1940 Table 4); but the major conclusions made for shielded gauges in his study can be applied to the U.S. Alter-shielded rain gauge and those made for his unshielded gauges to the U.S. unshielded gauges (these results are valid for a moderately windy site with a mean monthly wind at the gauge orifice height about 3 to 4 m s -• in the cold season and about 2 to 3 m s -t in the warm season). For central Ohio, the empirical estimate of losses is from Coshocton, Ohio [Riesbol, 1938[Riesbol, , 1940 Table 4); but the major conclusions made for shielded gauges in his study can be applied to the U.S. Alter-shielded rain gauge and those made for his unshielded gauges to the U.S. unshielded gauges (these results are valid for a moderately windy site with a mean monthly wind at the gauge orifice height about 3 to 4 m s -• in the cold season and about 2 to 3 m s -t in the warm season).…”