DOI: 10.5281/zenodo.18205988
title: LI-CCR: Dataset of daily lake ice evolution (2002-2024) across global cold climate regions based on gap-filled MODIS observations

description: The LI-CCR dataset provides global records of daily lake ice coverage (LIC), annual lake ice phenology (LIP), and the probability of complete ice-cover occurrence (PCIO) for 32,800 lakes across global cold climate regions. The dataset spans from 1 August 2002 to 31 July 2024, covering 22 complete freeze–thaw cycles in the Northern Hemisphere and 21 cycles in the Southern Hemisphere.



Lake ice coverage:


1.Lake_ice_coverage_with_uncertainty_for_individual_lake

Filename: named by the lake’s unique HydroLAKES identifier

Format: csv

Variable:'Date','Final_LIC','LIC_MODIS_Original','LIC_Added_Step2','LIC_Added_Step3','LIC_Added_Step4','LIC_Added_Cloud_allocted','LIC_Added_Reprocessing','Final_LIC_Quality','Final_LIC_Min','Final_LIC_Max' 

2.Quality_lake_ice_coverage_of_all_lakes

Filename: Quality_lake_ice_coverage_of_all_lakes

Format: csv

Variable:'Hrdro_id','Mean(Winter_LIC_MODIS_Original/Winter_Final_LIC)' ,'Mean(Winter_LIC_Added_Cloud_Removal/Winter_Final_LIC)', 'Mean(Winter_LIC_Added_Cloud_Alloction/Winter_Final_LIC)', 'Mean(Winter_LIC_Added_Reprocessing/Winter_Final_LIC)', 'Mean(Winter_Final_LIC_Quality/Winter_Final_LIC)'



Lake ice phenology:


1.Lake_ice_phenology

Filename: Lake_ice_phenology

Format: csv and gpkg

Variable: 'Hydro_id', 'FUS_2002', ‘FUE_2002’, 'BUS_2002', 'BUE_2002', 'ICD_2002', 'CICD_2002', 'FUS_2003', ‘FUE_2003’, 'BUS_2003', 'BUE_2003', 'ICD_2003', 'CICD_2003',...'FUS_2023', ‘FUE_2023’, 'BUS_2023', 'BUE_2023', 'ICD_2023', 'CICD_2023'

ps: (1) The year means the hydrological year. For example, for lakes in the Northern Hemisphere, the year of 2002 means the 1 August 2002 to 31 July 2003. (2) Day of Year (DOY) refers to the sequential day number within a calendar year, starting from January 1 as DOY 1 and increasing up to DOY 365 (or 366 in a leap year). In cases where an event spans across two calendar years (cross-year events), we adjust the DOY by adding the total number of days from the previous year. 

2.Quality_freeze_up_end_date

Filename: Quality_freeze_up_end_date

Format: csv

Variable: 'Hydro_id', '2002', '2003',..., '2023'

ps: An FUE records is flagged as '1' when all LIC values within the three-day window used for FUE extraction are derived from the reprocessing step.

3.Proportion_of_missing_original_MODIS_observations

Filename: Proportion_of_missing_original_MODIS_observations

Format: csv

Variable: 'Hydro_id', '2002', '2003',..., '2023'



Lake ice-cover status of each year for individual lake:


1.Lake_ice_phenology

Filename: Lake_ice-cover_status_of_each_year_for_individual_lake

Format: csv and gpkg

Variable: 'Hydro_id', '2002', '2003',..., '2023'

ps: 

2 means completely frozen, 1 means partilly frozen and 0 means unfrozen

2.Numbers_of_different_lake_ice-cover_status_of_each_year

Filename: Numbers_of_different_lake_ice-cover_status_of_each_year

Format: csv

Variable: 'Year', 'Number of completely frozen lakes', 'Number of partially frozen lakes', 'Number of unfrozen lakes'



Probability of complete ice-cover occurrence:


1.Probability of complete ice-cover occurrence

Filename: Probability of complete ice-cover occurrence

Format: csv and gpkg

Variable: Year and the probability of complete ice-cover occurrence (PCIO, 0-100%)

ps: The Probability of complete ice-cover occurrence refers to the number of years in which a lake becomes completely frozen divided by the total number of years within the study period.