A New Homogenized Climate Division Precipitation Dataset for Analysis of Climate Variability and Climate Change

Abstract

A new homogeneous climate division monthly precipitation dataset [based on full network estimated precipitation (FNEP)] was created as an alternative to the National Climatic Data Center (NCDC) climate division dataset. These alternative climate division monthly precipitation values were estimated using an equal-weighted average of Cooperative Observer Program stations that contained serially complete time series. Missing station observations were estimated by a procedure that was optimized through testing on U.S. Historical Climate Network stations. Inhomogeneities in the NCDC dataset arise from two principal causes. The pre-1931 estimation of NCDC climate division monthly precipitation from statewide averages led to a significant time series discontinuity in several climate divisions. From 1931 to the present, NCDC climate division averages have been calculated from a subset of available station data within each climate division, and temporal changes in the location of available stations have caused artificial changes in the time series. The FNEP climate division dataset is recommended over the NCDC dataset for studies involving climate trends or long-term climate variability. According to the FNEP data, the 1895-2009 linear precipitation trend is positive across most of the United States, and trends exceed 10% per century across the southern plains and the Corn Belt. Remaining inhomogeneities from changes in gauge technology and station location may be responsible for an artificial trend of 1%-3% per century.

Running dry: The U.S. Southwest's drift into a drier climate state

“…The strongest significant increasing trends occur in the Atlantic Northwest. This is in line with findings in recent studies [McRoberts and Nielsen-Gammon, 2011;Peterson et al, 2013;Balling and Goodrich, 2011]. Precipitation changes arise from both WT frequency and intensity changes.…”

“…The Northeast and Midwest regions of the contiguous United States (CONUS) show predominantly positive trends in observed annual mean precipitation since 1970, contrasting with decreases in parts of the U.S. Southwest (see Figure 1 for a definition of the regions) [McRoberts and Nielsen-Gammon, 2011;Peterson et al, 2013;Balling and Goodrich, 2011;Williams et al, 2015]. The number of days with very heavy precipitation also increased significantly in the U.S. Northeast [Karl and Melillo, 2009], while the U.S. Southwest has experienced a spate of droughts [Cayan et al, 2010] leading to economic losses of more than 100 billion dollars since 2000 [Smith and Katz, 2013].…”

Seasonal Climate Variability and Change in the Pacific Northwest of the United States

“…We used four observational datasets to better assess uncertainty of changes in the observational record: (i) daily and monthly maximum and minimum temperature and precipitation from 141 stations in the U.S. Historical Climate Network, version 2.5 (USHCN v2.5) (Menne et al 2009); (ii) gridded monthly temperature and precipitation from the ParameterElevation Regressions on Independent Slopes Model (PRISM) (Daly et al 2008); (iii) gridded monthly temperature and precipitation data from Climatic Research Unit (CRU) TS3.21 dataset (Harris et al 2013);and (iv) monthly temperature from the U. S. climate division dataset from the National Climatic Data Center (NCDC) and monthly precipitation from the U.S. climate division dataset adjusted for inhomogeneities (McRoberts and Nielsen-Gammon 2011). The latter three datasets were considered for the time period 1901-2012.…”

Understanding changes in water availability in the Rio Grande/Río Bravo del Norte basin under the influence of large‐scale circulation indices using the Noah land surface model

“…The data set undergoes extensive quality control including adjustment for any time‐of‐observation bias. Only 27 stations out of the 1,221 stations in the USHCN are serially complete [ McRoberts and Nielsen‐Gammon , 2011], while missing data in the others have been filled using a weighted average of values from highly correlated neighboring stations. However, the density of the USHCN network is not adequate within RG for purposes of this study (see Figure 1 of USHCN Version 2 Serial Monthly Data set, available from http://www.ncdc.noaa.gov/oa/climate/research/ushcn/, which shows the distribution of both COOP and HCN sites).…”

“… McRoberts and Nielsen‐Gammon [2011] proposed the full network estimated precipitation (FNEP, available from http://atmo.tamu.edu/osc/fnep) which utilizes as many COOP observations from the network of more than 24,000 stations and an inverse distance weighting scheme, using stations that have at least 10 years of overlap data and highest correlation, to fill missing data and extend the record, thus creating a continuous series from 1895 to present. There are a total of 332 FNEP stations within the U.S. portion of RG, but only those that have a sufficiently long record of observational data, while ensuring adequate spatial coverage, were chosen, hence taking advantage of the filled gaps.…”