Arctic lakes ice break-up timing for 2000 - 2013

This dataset includes break-up start and break-up end dates for 13 300 lakes larger than 1 km2 in five study areas in the Arctic. The dates were derived using time-series of daily surface reflectance data at 250m spatial resolution acquired by the Moderate Resolution Imaging spectroradiometer (MODIS) aboard the TERRA satellite.

Detailed description of the methodology, validation and analysis is available in:
Šmejkalová, Tereza, Mary Edwards, and Jadunandan Dash. “Arctic Lakes Show Strong Decadal Trend in Earlier Spring Ice-Out.” Scientific Reports 6 (December 7, 2016): 38449. https://doi.org/10.1038/srep38449.
Šmejkalová, Tereza. “Quantifying Decadal Changes in Arctic Lake Ice Phenology.” MSc. Thesis, Southampton, University of Southampton.

Šmejkalová 2014 and Šmejkalová, Edwards, and Dash 2016.

Parameters: Break-up start (BUS) - The day of year when ice-free water appears. (Lat/Lon lake centroid)
Break-up end (BUE) – The day of year when water is completely ice-free. (Lat/Lon lake centroid)

Spatial coverage: Northern Europe (> 65°N)
Northeast Canada (mainland; > 65°N; 85°- 105°E)
Alaskan Arctic Coastal Plain (> 69°N; 150°- 160°E)
Northeast Siberia (> 67°N; 140°- 165°W)
Central Siberia (70°- 75°N; 90°- 110°W)
Spatial resolution: Lakes larger than 1 km2
Temporal coverage: 1 year
Temporal resolution: 2000-2013 (not all years available for all lakes)
Data formats: CSV (Coma Separated Values, *.csv)
ESRI Shapefile (*.shp)

Files: Alaska_ACP_BUS.csv
Alaska_ACP_BUE.csv
C_Siberia_BUS.csv
C_Siberia_BUE.csv
N_Europe_BUS.csv
N_Europe_BUE.csv
NE_Canada_BUS.csv
NE_Canada_BUE.csv
NE_Siberia_BUS.csv
NE_Siberia_BUE.csv
Auxiliary data: Lake_polygons_1km2_Alaska_ACP.shp [EPSG 3995; WGS 84 / Arctic Polar Stereographic]
Lake_polygons_1km2_C_Siberia.shp [EPSG 3995; WGS 84 / Arctic Polar Stereographic]
Lake_polygons_1km2_NE_Canada.shp [EPSG 3995; WGS 84 / Arctic Polar Stereographic]
Lake_polygons_1km2_N_Europe.shp [EPSG 3995; WGS 84 / Arctic Polar Stereographic]
Lake_polygons_1km2_NE_Siberia.shp [EPSG 3995; WGS 84 / Arctic Polar Stereographic]
Study_areas.shp [EPSG 3995; WGS 84 / Arctic Polar Stereographic]

本数据集涵盖北极地区5个研究区内13300个面积大于1平方千米的湖泊的冰消融起始与结束日期。上述日期通过搭载于TERRA卫星的中分辨率成像光谱仪（Moderate Resolution Imaging Spectroradiometer, MODIS）获取的250米空间分辨率逐日地表反射率时间序列数据反演得到。

有关该数据集的方法学、验证与分析细节可参阅以下文献：
Šmejkalová, Tereza、Mary Edwards与Jadunandan Dash：《北极湖泊春季冰消呈现显著年代际提前趋势》，载于《科学报告》2016年12月7日第6卷，第38449页，DOI: 10.1038/srep38449。
Šmejkalová, Tereza：《北极湖泊冰物候的年代际变化量化》，南安普敦大学（University of Southampton）硕士学位论文，南安普敦。
即Šmejkalová（2014）与Šmejkalová、Edwards及Dash（2016）。

参数说明：
冰消融起始日期（Break-up Start, BUS）：指无冰水面首次出现的儒略日，对应湖泊质心的经纬度坐标。
冰消融结束日期（Break-up End, BUE）：指水体完全无冰的儒略日，对应湖泊质心的经纬度坐标。

空间覆盖范围：
北欧（北纬65°以北）
加拿大东北部（本土区域；北纬65°以北，东经85°-105°）
阿拉斯加北极海岸平原（北纬69°以北，东经150°-160°）
西伯利亚东北部（北纬67°以北，西经140°-165°）
西伯利亚中部（北纬70°-75°，西经90°-110°）

空间分辨率：仅涵盖面积大于1平方千米的湖泊
时间覆盖范围：单年度
时间分辨率：2000-2013年（并非所有湖泊均拥有全部年份的有效数据）

数据格式：
逗号分隔值格式（Comma Separated Values, *.csv）
ESRI形状文件（*.shp）

文件列表：
Alaska_ACP_BUS.csv
Alaska_ACP_BUE.csv
C_Siberia_BUS.csv
C_Siberia_BUE.csv
N_Europe_BUS.csv
N_Europe_BUE.csv
NE_Canada_BUS.csv
NE_Canada_BUE.csv
NE_Siberia_BUS.csv
NE_Siberia_BUE.csv

辅助数据：
Lake_polygons_1km2_Alaska_ACP.shp [EPSG 3995; WGS 84 / 北极极射投影]
Lake_polygons_1km2_C_Siberia.shp [EPSG 3995; WGS 84 / 北极极射投影]
Lake_polygons_1km2_NE_Canada.shp [EPSG 3995; WGS 84 / 北极极射投影]
Lake_polygons_1km2_N_Europe.shp [EPSG 3995; WGS 84 / 北极极射投影]
Lake_polygons_1km2_NE_Siberia.shp [EPSG 3995; WGS 84 / 北极极射投影]
Study_areas.shp [EPSG 3995; WGS 84 / 北极极射投影]