This readme.txt file was generated in May 2024 by Christopher Rounds (round060@umn.edu) ------------------- GENERAL INFORMATION ------------------- 1. Title of Dataset Minnesota lake ice phenology 2. Author Information Principal Investigator Contact Information Name: Jake Walsh Institution: University of Minnesota, Department of Fisheries and Wildlife Email: walsh229@gmail.com ORCID: https://orcid.org/0000-0003-2292-6106 Associate or Co-investigator Contact Information Name: Kelsey Vitense Institution: University of Minnesota, Department of Fisheries and Wildlife ORCID: https://orcid.org/0000-0003-2455-5513 Associate or Co-investigator Contact Information Name: Christopher Rounds Institution: University of Minnesota, Department of Fisheries and Wildlife Email: round060@umn.edu ORCID: https://orcid.org/0000-0003-1346-5707 Associate or Co-investigator Contact Information Name: Kenneth Blumenfeld Institution: Minnesota Department of Natural Resources State Climatology Office Email: kenneth.blumenfeld@state.mn.us ORCID: https://orcid.org/0009-0009-5321-8920 Associate or Co-investigator Contact Information Name: Peter Boulay Institution: Minnesota Department of Natural Resources State Climatology Office Email: pboulay@umn.edu ORCID: https://orcid.org/0009-0005-0980-4069 Associate or Co-investigator Contact Information Name: Gretchen JA Hansen Institution: University of Minnesota, Department of Fisheries and Wildlife Email: ghansen@umn.edu ORCID: https://orcid.org/0000-0003-0241-7048 3. Date of data collection (single date, range, approximate date) 1840 - 2023 4. Geographic location of data collection (where was data collected?): Minnesota -------------------------- SHARING/ACCESS INFORMATION -------------------------- 1. Was data derived from another source? If yes, list source(s): Data is collated and maintained by the Minnesota Department of Natural Resources State Climatology Office. 2. 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/policies/#drum-terms-of-use --------------------- DATA & FILE OVERVIEW --------------------- 1. File List A. Filename: ice_duration.csv Short description: Data includes lake ice duration data for Minnesota lakes from the earliest records through the winter of 2023. B. Filename: ice_in.csv Short description: Data includes lake ice in (ice formation) data for Minnesota lakes from the earliest records through the winter of 2023. C. Filename: ice_out.csv Short description: Data includes lake ice out (ice melt) data for Minnesota lakes from the earliest records through the winter of 2023. D. Filename: ice_drum.r Short description: reads in ice_in.csv and ice_out.csv and creates ice_duration.csv through an inner join on winter.year and DOW. E. Filename: ice_drum.rproj Short description: R project file for ice_drum.r 2. Relationship between files: ice_duration.csv is built from an inner join of ice_in.csv and ice_out.csv by DOW and winter.year (see ice_drum.r). -------------------------- METHODOLOGICAL INFORMATION -------------------------- 1. Description of methods used for collection/generation of data: Lake ice in and ice out are monitored by a variety of different organizations including state agencies, lake association members and community scientists. The Minnesota State Climatology Office collates historic and contemporary records of lake ice in and out. The definition of lake ice in and out can vary from lake to lake but observers generally use consistent criteria for determining the data ice formation occurs or ice melts for a lake. For more information see the Minnesota DNR lake ice in (https://www.dnr.state.mn.us/ice_in/index.html) and ice out (https://www.dnr.state.mn.us/ice_out/index.html) websites. 2. Methods for processing the data: Data are relatively unprocessed from the Minnesota State Climatology Office. 3. Describe any quality-assurance procedures performed on the data: Data is checked to make sure no columns are missing data and dates are formatted consistently. ----------------------------------------- DATA-SPECIFIC INFORMATION FOR: ice_duration.csv ----------------------------------------- 1. Number of variables: 20 2. Number of cases/rows: 9,165 3. Variable List A. Name: DOW Description: Department of Waterbody Lake ID. Used as an identifier for different lakes in Minnesota. B. Name: winter.year Description: The winter year of the observation. If the ice came on in fall of 2000 and melted in spring of 2001 the winter.year variable would be 2001. C. Name: min_ice_on_julian Description: The recorded julian day of year of ice on for the waterbody-year combination that gives the minimum ice duration. If there are two different measurements for day of ice on min_ice_on_julian is the day that comes later. D. Name: max_ice_on_julian Description: The latest recorded julian day of year of ice on. min_ice_on_julian and max_ice_on_julian will be the same if there is only one ice on record for that year-lake combination and will be different if there are records of ice on occuring on two or more different days. E. Name: min_ice_on_date Description: The recorded date of ice on for the waterbody-year combination that gives the minimum ice duration. Formatted as "YYYY-MM-DD". F. Name: max_ice_on_date Description: The recorded date of ice on for the waterbody-year combination that gives the maximum ice duration. min_ice_on_date and max_ice_on_date will be the same if there is only one ice on record for that year-lake combination and will be different if there are records of ice on occuring on two or more different days. Formatted as "YYYY-MM-DD". G. Name: N_ice_on Description: The number of times ice on was recorded for a given lake-year combination. H. Name: range_ice_on Description: The range in days of the different ice on records in a given lake-year. If there is only one ice on record the range is zero. I. Name: max_ice_on_julian2 Description: Same as the max_ice_on_julian column but if the ice freeze doesn't happen until after the new year 365 (or 366 if the previous year was a leap year) is added to the column. Fixes very low julian day values that make visualizations and modeling difficult. Ex - if max_ice_on_julian = 5 then max_ice_on_julian2 = 5 + 365. J. Name: min_ice_on_julian2 Description: Same as the min_ice_on_julian column but if the ice freeze doesn't happen until after the new year, 365 (or 366 if the previous year was a leap year) is added to the column. Fixes very low julian day values that make visualizations and modeling difficult. K. Name: min_ice_off_julian Description: The earliest recorded julian day of year of ice off for the waterbody-year combination. L. Name: max_ice_off_julian Description: The latest recorded julian day of year of ice off. min_ice_off_julian and max_ice_off_julian will be the same if there is only one ice off record for that year-lake combination and will be different if there are records of ice off occurring on two or more different days. M. Name: min_ice_off_date Description: The earliest recorded date of ice off for the waterbody-year combination. Formatted as "YYYY-MM-DD". N. Name: max_ice_off_date Description: The latest recorded date of ice on for the waterbody-year combination. min_ice_off_date and max_ice_off_date will be the same if there is only one ice off record for that year-lake combination and will be different if there are records of ice off occurring on two or more different days. Formatted as "YYYY-MM-DD". O. Name: N_ice_off Description: The number of times ice off was recorded for a given lake-year combination. P. Name: range_ice_off Description: The range in days of the different ice on records in a given lake-year. If there is only one ice on record the range is zero. Q. Name: ID Description: The DOW with the prefix "DOW_". Used to keep the unique ID as a non-numeric. R. Name: fall.year Description: The fall year of the observation. If the ice came on in fall of 2000 and melted in the spring of 2001 the fall.year variable would be 2000. S. Name: max_duration Description: The maximum duration of ice in a given lake-year combination. If there are two or more measurements for ice on the earlier measurement is used (such as min_ice_on_julian), if there are two or more measurements for ice off the later measurement is used (such as max_ice_off_julian). T. Name: min_duration Description: The minimum duration of ice in a given lake-year combination. If there are two or more measurements for ice on the later measurement is used (such as max_ice_on_julian), if there are two or more measurements for ice off the earlier measurement is used (such as min_ice_off_julian). ----------------------------------------- DATA-SPECIFIC INFORMATION FOR: ice_in.csv ----------------------------------------- 1. Number of variables: 10 2. Number of cases/rows: 11,065 3. Variable List A. Name: DOW Description: Department of Waterbody Lake ID. Used as an identifier for different lakes in Minnesota. B. Name: winter.year Description: The winter year of the observation. If the ice came on in fall of 2000 and melted in spring of 2001 the winter.year variable would be 2001. C. Name: min_ice_on_julian Description: The recorded julian day of year of ice on for the waterbody-year combination that gives the minnimum ice duration. If there are two different measurements for day of ice on min_ice_on_julian is the day that comes later. D. Name: max_ice_on_julian Description: The recorded julian day of year of ice on for the waterbody-year combination that gives the maximum ice duration. min_ice_on_julian and max_ice_on_julian will be the same if there is only one ice on record for that year-lake combination and will be different if there are records of ice on occuring on two or more different days. E. Name: min_ice_on_date Description: The earliest recorded date of ice on for the waterbody-year combination. Formatted as "YYYY-MM-DD". F. Name: max_ice_on_date Description: The latest recorded date of ice on for the waterbody-year combination. min_ice_on_date and max_ice_on_date will be the same if there is only one ice on record for that year-lake combination and will be different if there are records of ice on occuring on two or more different days. Formatted as "YYYY-MM-DD". G. Name: N_ice_on Description: The number of times ice on was recorded for a given lake-year combination. H. Name: range_ice_on Description: The range in days of the different ice on records in a given lake-year. If there is only one ice on record the range is zero. I. Name: max_ice_on_julian2 Description: Same as the max_ice_on_julian column but if the ice freeze doesn't happen until after the new year 365 (or 366 if the previous year was a leap year) is added to the column. Fixes very low julian day values that make visualizations and modeling difficult. Ex - if max_ice_on_julian = 5 then max_ice_on_julian2 = 5 + 365. J. Name: min_ice_on_julian2 Description: Same as the min_ice_on_julian column but if the ice freeze doesn't happen until after the new year, 365 (or 366 if the previous year was a leap year) is added to the column. Fixes very low julian day values that make visualizations and modeling difficult. ----------------------------------------- DATA-SPECIFIC INFORMATION FOR: ice_out.csv ----------------------------------------- 1. Number of variables: 10 2. Number of cases/rows: 20,016 3. Variable List A. Name: DOW Description: Department of Waterbody lake ID. Used as an identifier for different lakes in Minnesota. B. Name: min_ice_off_julian Description: The earliest recorded julian day of year of ice off for the waterbody-year combination. C. Name: max_ice_off_julian Description: The latest recorded julian day of year of ice off. min_ice_off_julian and max_ice_off_julian will be the same if there is only one ice off record for that year-lake combination and will be different if there are records of ice off occurring on two or more different days. D. Name: min_ice_off_date Description: The earliest recorded date of ice off for the waterbody-year combination. Formatted as "YYYY-MM-DD". E. Name: max_ice_off_date Description: The latest recorded date of ice on for the waterbody-year combination. min_ice_off_date and max_ice_off_date will be the same if there is only one ice off record for that year-lake combination and will be different if there are records of ice off occurring on two or more different days. Formatted as "YYYY-MM-DD". F. Name: N_ice_off Description: The number of times ice on was recorded for a given lake-year combination. G. Name: range_ice_off Description: The range in days of the different ice on records in a given lake-year. If there is only one ice on record the range is zero. H. Name: winter.year Description: The winter year of the observation. If the ice came on in fall of 2000 and melted in spring of 2001 the winter.year variable would be 2001. I. Name: ID Description: The DOW with the prefix "DOW_". Used to keep the unique ID as a non-numeric. J. Name: fall.year Description: The fall year of the observation. If the ice came on in fall of 2000 and melted in the spring of 2001 the fall.year variable would be 2000. Results from sessionInfo() in the drum_ice.R file R version 4.1.2 (2021-11-01) Platform: x86_64-w64-mingw32/x64 (64-bit) Running under: Windows 10 x64 (build 22631) Matrix products: default locale: [1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252 [3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C [5] LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] lubridate_1.9.3 forcats_1.0.0 stringr_1.5.0 dplyr_1.1.3 [5] purrr_1.0.1 readr_2.1.4 tidyr_1.3.0 tibble_3.2.1 [9] ggplot2_3.4.1 tidyverse_2.0.0.9000 loaded via a namespace (and not attached): [1] rstudioapi_0.15.0 magrittr_2.0.3 hms_1.1.3 tidyselect_1.2.0 munsell_0.5.0 [6] timechange_0.2.0 colorspace_2.0-3 R6_2.5.1 rlang_1.1.2 fansi_1.0.3 [11] tools_4.1.2 grid_4.1.2 gtable_0.3.1 utf8_1.2.2 cli_3.6.1 [16] withr_2.5.2 lifecycle_1.0.3 tzdb_0.2.0 vctrs_0.6.1 glue_1.6.2 [21] stringi_1.7.8 compiler_4.1.2 pillar_1.9.0 generics_0.1.2 scales_1.2.1 [26] pkgconfig_2.0.3