This readme.txt file was generated on 20240307 by Stefan Liess Recommended citation for the data: Smoliak, B. V., P. K. Snyder, T. E. Twine, P. M. Mykleby, and W. F. Hertel (2024). Temperature Observations of the Twin Cities Canopy-Layer Urban Heat Island. Retrieved from the Data Repository for the University of Minnesota (DRUM), https://doi.org/10.13020/r4pc-4x10. ------------------- GENERAL INFORMATION ------------------- 1. Title of Dataset Temperature Observations of the Twin Cities Canopy-Layer Urban Heat Island 2. Author Information Smoliak, Brian V., Peter K. Snyder, Tracy E. Twine, Phillip M. Mykleby, William F. Hertel, and Stefan Liess Principal Investigator Contact Information Name: Tracy E Twine Institution: Dept. Soil, Water, and Climate, University of Minnesota Address: 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108 Email: twine@umn.edu ORCID: 0000-0002-8457-046X Associate or Co-investigator Contact Information Name: Peter K Snyder Institution: Dept. Soil, Water, and Climate, University of Minnesota Address: 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108 Email: snyderpk@umn.edu ORCID: 0000-0002-4711-9426 3. Date published or finalized for release: 2014-08-01 4. Date of data collection 2011-08-01 - 2014-08-01 5. Geographic location of data collection (where was data collected?): Twin-Cities Metro Area 6. Information about funding sources that supported the collection of the data: This research was funded by the University of Minnesota Institute on the Environment under Discovery Grant DG-0015-11 and the U.S. National Science Foundation under Grant 1231325. 7. Overview of the data (abstract): Data from a dense urban meteorological network (UMN) are analyzed, revealing the spatial heterogeneity and temporal variability of the Twin Cities (Minneapolis–St. Paul, Minnesota) canopy-layer urban heat island (UHI). Data from individual sensors represent surface air temperature (SAT) across a variety of local climate zones within a 5000-km2 area and span the 3-yr period from 1 August 2011 to 1 August 2014. Irregularly spaced data are interpolated to a uniform 1-km x 1-km grid using two statistical methods: 1) kriging and 2) cokriging with impervious surface area data. The cokriged SAT field exhibits lower bias and lower RMSE than does the kriged SAT field when evaluated against an independent set of observations. Maps, time series, and statistics that are based on the cokriged field are presented to describe the spatial structure and magnitude of the Twin Cities metropolitan area (TCMA) UHI on hourly, daily, and seasonal time scales. The average diurnal variation of the TCMA UHI exhibits distinct seasonal modulation wherein the daily maximum occurs by night during summer and by day during winter. Daily variations in the UHI magnitude are linked to changes in weather patterns. Seasonal variations in the UHI magnitude are discussed in terms of land–atmosphere interactions. To the extent that they more fully resolve the spatial structure of the UHI, dense UMNs are advantageous relative to limited collections of existing urban meteorological observations. Dense UMNs are thus capable of providing valuable information for UHI monitoring and for implementing and evaluating UHI mitigation efforts. -------------------------- SHARING/ACCESS INFORMATION -------------------------- 1. Licenses/restrictions placed on the data: Attribution-NonCommercial-NoDerivs 3.0 United States (http://creativecommons.org/licenses/by-nc-nd/3.0/us/) 2. Links to publications that cite or use the data: Smoliak, B. V., P. K. Snyder, T. E. Twine, P. M. Mykleby, and W. F. Hertel, 2015: Dense Network Observations of the Twin Cities Canopy-Layer Urban Heat Island. J. Appl. Meteor. Climatol., 54, 1899–1917, https://doi.org/10.1175/JAMC-D-14-0239.1. 3. Terms of Use: Data Repository for the U of Minnesota (DRUM) By using these files, users agree to the Terms of Use. https://conservancy.umn.edu/pages/drum/policies/#terms-of-use --------------------- DATA & FILE OVERVIEW --------------------- 1. File List A. Filename: README.txt Short description: This file. B. Filename: Instrument.zip Short description: Direct measurements as Level0 (measurements downloaded as CSV files), Level1 (converted to netCDF format), and Level2 (removing outliers, calculating daily and hourly average values, and providing th error logs) Folder structure: └───HOBO ├───Level0 │ ├───download (CSV for each sensor, refers to the month when data were downloaded) ├───Level1 (201 NetCDF files, one per sensor) ├───Level2 (201 NetCDF files, one per sensor) │ ├───daily (199 NetCDF files, one per sensor where appropriate) │ ├───error_logs (201 TXT files, one per sensor) │ └───hourly (201 NetCDF files, one per sensor) └───Metadata (XLSX file about active sensor times and sensor locations) C. Filename: Grid.zip Short description: Data interpolated to 1-km x 1-km regular grids using kriging and alternatively co-kriging methods Folder structure: └───Gridded ├───cokrige (1 NetCDF map file for all times) │ └───hourly (25,041 intermediate NetCDF map files for each hour) └───krige (1 NetCDF map file for all times) └───hourly (24,662 intermediate NetCDF map files for each hour) 2. Relationship between files: Grid.zip uses input from Level2 folder of Instrument.zip -------------------------- METHODOLOGICAL INFORMATION -------------------------- 1. Description of methods used for collection/generation of data and instrument- or software-specific information Detailed information available in the open access publication: Smoliak, B. V., P. K. Snyder, T. E. Twine, P. M. Mykleby, and W. F. Hertel, 2015: Dense Network Observations of the Twin Cities Canopy-Layer Urban Heat Island. Journal of Applied Meteorology and Climatology., 54, 1899–1917, https://doi.org/10.1175/JAMC-D-14-0239.1. 2. Methods for processing the data: Kriging is described in Journel, A. G., and C. J. Huijbregts, 1978: Mining Geostatistics. Academic Press, 600 pp. and Kawashima, S., and T. Ishida, 1992: Effects of regional temperature, wind speed and soil wetness on spatial structure of surface air temperature. Theoretical and Applied Climatology, 46, 153–161, doi:10.1007/BF00866095. Co-kriging is described in Ishida, T. and S. Kawashima, 1993: Use of cokriging for air temperature. Theoretical and Applied Climatology, 47, 147–157, doi:10.1007/BF00867447. ----------------------------------------- DATA-SPECIFIC INFORMATION: ----------------------------------------- 1. Missing data codes: Code/symbol nan Definition Data removed in Level2 as unreliable Code/symbol missing Definition Data unavailable 2. Variable List A. Name: temperature (T) in degree Fahrenheit for CSV files and degree Celsius for NetCDF files Description: Canopy-level temperature