Precipitation records

The precipitation record shows a mild decrease in rainfall for May, June, and July over the last 20 years of record. However, runoff decreased to less than half the historical average for May and June over the same period, and reduced runoff persisted into December, despite a return to normal or above normal precipitation levels over the latter half of the year. 

Atkinson TC, Rowe PJ (1992) Applications of dating to denudation chronology and landscape evolution. In Uranium-series disequilibriiun Applications to Earth, Marine and Enviromnental Sciences, Ivanovich M, Harmon RS (eds) Oxford University Press, Oxford, p 669-703 Auler AS, Smart PL (2001) Late Quaternary paleoclimate in semiarid Northeastern Brazil from U-series dating of travertines and water table speleothems. Quat Res 55 159-167 Ayliffe LK, Marianelh PC, Moriarty KC, Wells RT, McCulloch MT, Mortimer GE, Hellstrom JC (1998) 500 ka precipitation record from southeastern Australia Evidence for interglacial relative aridity. Geology 26 147-150... 

Teegavarapu RSV, Chandramouli V (2005) Improved weighting methods, deterministic and stochastic data-driven models for estimation of missing precipitation records. J Hydrol 312 191-206... 

A continuous, dynamic, one-dlmenslonal model called the Pesticide Root Zone Model or PRZM, has been developed recently by EPA/ORD In Athens, Georgia (110). PRZM allows for varying hydrologic and chemical properties by soil horizon. Weather data for water flow modeling Is obtained from dally precipitation records of the National Weather Service. It has been successfully validated with atrazlne field data from Watklns-vllle, Georgia and aldlcarb data from Long Island, New York for depths less than 3 meters. 

Place in separate clean, dry test tubes (100 X 13 mm) 2 mL of distilled water and 2 mL of the residue liquid from the boiling flask. Add to each sample 5 drops of silver nitrate solution. Look for the appearance of a white precipitate. Record your observations. Silver ions combine with chloride ions to form a white precipitate of silver chloride. 

NaOH (dropwise) until the solution becomes colorless. Keep the test tubes in the warm water bath for 5 min. Remove the test tubes from the water, let cool, and look for a light yellow precipitate. Record your observations on the Report Sheet (3). The formation of the yellow precipitate tends to be slow. Put these test tubes to one side and make your observations when all the other tests are completed. 

Step 6. Place each filter in a filter holder, identical to that used in the procedure. Count as soon as possible (within several hours) after the precipitation. Record gross count rates and background count rate in Data Table 13.3. 

Answer 4.5 The water table curve in Fig. 4.8 is not correlated to the precipitation record (no match of peaks). The reason the well is recharged by various sources not included in the precipitation record—recharge is by the time of snowmelt and not by the time of snow fall. In addition, water demands are not reflected in the precipitation record. In other cases the... 

In practice, before any monitoring is done, the as-built sewer system plans must first be obtained to determine where the monitoring apparatus should be set. Once this is established, the contributing population must also be determined. This population is used to normalize the measured flow rates on a per capita basis in order for the data to be transportable and, most important, the nearby precipitation record should be consulted to determine the months for the dry and wet seasons. If the purpose of the field survey is to determine the dry-weather flows, then the monitoring should be done on the dry-weather months as evidenced from the records of the nearby precipitation station. If the purpose of the field survey is to determine infiltration, then the monitoring should be done on the wet-weather months, again, as evidenced from the records of the nearby precipitation station. In Maryland, the dry-weather months are normally June to August. 

Strict adherence to the assumption of constant Pb flux is somewhat relaxed in practice, depending on the time scale of interest. Because Pb deposition in precipitation is a stochastic process, the actual flux will vary widely over short periods. These fluctuations are effectively integrated, however, by taking samples representing the accumulation of several years. No long-term measurements of atmospheric Pb are available, but the lack of a significant secular trend in annual precipitation recorded in New Haven over the last century or so (Kirk, 1939 U.S. Dept, of Commerce, 1972), and the lack of demonstrable fission-produced Pb (Beasley, 1%9 Feeley and Seitz, 1970), make the assumption of a constant Pb flux seem reasonable. 

The deposition of tritium to the oceans occurs both by direct precipitation and by vapor exchange. Vapor exchange is a two-way process, and in general dominates over the direct precipitation. There are relatively few direct measures of tritium concentration in atmospheric water vapor, but studies indicate that it is closely related to levels in precipitation. This linkage has been exploited in order to construct tritium depositional histories for ocean basins from tritium in precipitation records. 

A 1500-year record of tropical precipitation recorded in ice cores from the Quelccaya Ice Cap, Peru. Science 229(4717) 971-973... 

Huff, F. A. (1971). Evaluation of precipitation records in weather modification experiments. In H. Landsbeig J. Van Mieghem Advances in geophysics (Vol. 15, pp. 60-135). New York Academic. 

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