README file for the Web-Accessible Folder of nClimGrid-Daily's Gridded Fields and Area Averages, v1.0.0 Last updated: 23 September 2022 PURPOSE ======= The nClimGrid-Daily product consists of daily gridded fields and area averages of maximum, minimum, and average temperatures as well as of precipitation for the contiguous United States from 1951 to present. The product was developed, and is maintained, at NOAA's National Centers for Environmental Information (NCEI) and is made available through various web-based distribution channels. One of these distribution mechanisms is NCEI's web-accessible folder (WAF) at https://www.ncei.noaa.gov/data/nclimgrid-daily/, and it is the purpose of this file to describe the contents of that folder. Additional information on nClimGrid-Daily can be found in the nClimGrid-Daily User Guide and on the nClimGrid-Daily webpage at https://www.ncei.noaa.gov/products/land-based-station/nclimgrid-daily. CONTENTS ======== The contents of this folder is organized into three directories which are described below. Directory access/: ------------------ This directory contains uncompressed files for gridded fields and area averages. Subdirectory access/grids/ contains the gridded fields. Subdirectory access/averages/ contains the area averages. Gridded fields are organized into one Network Common Data Format (NetCDF) file per year-month, and area averages are stored in a total of 36 comma-separated value (CSV) files per month (four variables times nine types of regions). Files are organized into year-by-year subdirectories. For each month, a version identification file is provided along with the data file(s). This version identification file is the same for the gridded fields as for the area averages. The uncompressed files are recommended for users browsing the data, applications using HTTP requests for downloading specific sets of files, users needing to download a single file, and users interested in downloading data for just one area type. Directory archive/: ------------------- This directory contains monthly tar.gz files (i.e., compressed collections) of the files in the access/ subdirectory. Each tar file contains 37 data files (1 gridded field and 36 area average files) plus one version identification file. These files are particularly suitable for direct download and are recommended for users interested in downloading the area averages over a long period of years. Directory doc/: --------------- This directory contains the following documentation files: nClimGrid-Daily_v1-0-0_readme-web.txt: this file nclimgrid-daily_v1-0-0_user-guide.pdf: This document provides basic information, references with additional information, and points of contact for nClimGrid-Daily. nclimgrid-daily_status-web.txt: This file describes the status of the product in this folder. us-state-codes_ncei-to-fips.csv: This file provides a cross-reference between the NCEI state codes and the Federal Information Processing System (FIPS) state codes. DATA FILENAMES ============== File names are of the form ncdd-YYYYMM-grd-SSSSSS.nc for grid files and EEEE-YYYYMM-RRR-SSSSSS.csv for area-average files, where ncdd stands for "nClimGrid-Daily data", and the capital letters have the following meanings: EEEE is the meteorological element, or variable. It has four possible values: prcp = Precipitation (mm) tavg = Average temperature (°C), the average of tmax and tmin tmax = daily maximum temperature (°C) tmin = daily minimum temperature (°C) YYYY is the year and ranges from 1951 to the current year. MM is the current month and ranges from 01 for January to 12 for December. RRR is the type of region to which the values in the file apply. It can take the following values: cen = census tracts cns = Contiguous U.S. cty = Counties div = Climate divisions hc1 = Hydrologic Unit Code (HUC) 1 watersheds nca = NCA regions reg = NCEI regions ste = state wfo = Weather Forecast Office (WFO) SSSSSS is the file status. It can take one of two values: prelim = Preliminary, indicating that the values in the file have not been scaled to match the corresponding values from the monthly nClimGrid product. scaled = Scaled, indicating that the values in the file have been adjusted to match corresponding monthly values For example, pncdd-201712-grd-scaled.nc contains the gridded fields for each day of December 2017, and tmax-202209-ste-prelim.csv contains the preliminary average of daily maximum temperature for each of the 48 contiguous states for each day in September 2022. Note that the prelim files will be updated daily. Once a "scaled" set has been created for a month for which all data are available, the corresponding "prelim" file will be removed. FORMAT OF THE CSV FILES OF AREA AVERAGES ======================================== Each of the CSV files contains one record per geographic entity. For example, the file containing state averages for one variable, year, and month has one record for each of the 48 states in the contiguous U.S. The first three columns identify the region type, region code, and region name. For example, corresponding entries for the state of North Carolina are ste, 31, North Carolina. Numeric identifiers for U.S. states, which are also contained in the county and climate division identifiers, follow the NCEI numbering system that is used in the station identifiers of sites within the U.S. Cooperative Observer Network: 01 Alabama 02 Arizona 03 Arkansas 04 California 05 Colorado 06 Connecticut 07 Delaware 08 Florida 09 Georgia 10 Idaho 11 Illinois 12 Indiana 13 Iowa 14 Kansas 15 Kentucky 16 Louisiana 17 Maine 18 Maryland 19 Massachusetts 20 Michigan 21 Minnesota 22 Mississippi 23 Missouri 24 Montana 25 Nebraska 26 Nevada 27 New Hampshire 28 New Jersey 29 New Mexico 30 New York 31 North Carolina 32 North Dakota 33 Ohio 34 Oklahoma 35 Oregon 36 Pennsylvania 37 Rhode Island 38 South Carolina 39 South Dakota 40 Tennessee 41 Texas 42 Utah 43 Vermont 44 Virginia 45 Washington 46 West Virginia 47 Wisconsin 48 Wyoming For convenience, a supplementary cross-reference between these NCEI state codes and the Federal Information Processing System (FIPS) state codes is provided. The fourth and fifth columns identify the four-digit year and two-digit month. Example: 1951,01. The sixth column identifies the variable: PRCP = precipitation (mm); TAVG, TMAX, and TMIN = average, maximum, minimum temperature (degrees Celsius), respectively. The remaining 31 columns provide the values of the specified variable on each day of the given month. These values are provided in fixed-width format of the form %8.2f, i.e., as a real number with two significant digits. Values on nonexistent days such as February 30 are set to -999.99. CONTACT INFORMATION =================== Please email ncei.grids@noaa.gov for technical questions about this product and ncei.orders@noaa.gov for support accessing this product.