ARC-Lake – Data Product Description Version v1.0 22nd September 2010 1st release v1.1 22nd March 2011 2nd release v1.1.1 31st March 2011 Update to some 2nd release data products v1.1.2 15th April 2011 Update to some 2nd release data products v3.0 17th January 2014 v3.0 data products Release Notes v1.0 First official release of ARC-Lake lake surface temperature (LSWT) and lake ice concentration (LIC) products. Draft Data Product Description (22/09/2010). v1.1 Second release of ARC-Lake lake surface water temperature (LSWT) and lake ice concentration (LIC) products. 1. Salinity dependent emissivity. 2. Modification of ice-detection algorithm to reduce classification of clouds as ice. 3. New methods of handling ice and periods of no observations in reconstructions. v1.1.1 Update to v1.1. 1. Change in methodology for deriving averaged data products based on observations. Details of the new method are given in the Averaging Methods section. 2. Correction to NLSWT and NICE fields in global spatially-resolved averaged products. 3. Correction to LAKEID field in global lake-mean averaged products. v1.1.2 Update to v1.1. 1. Change in methodology for deriving averaged data products based on observations. Pre- filtering to remove observations with high χ2 (as applied in derivation of reconstructions). 2. Removal of redundant variables and attributes from per-lake data products. v3.0 Release of ARC-Lake v3.0 data products. 1. Expansion of dataset to include smaller lakes and reservoirs. 2. Introduction of water detection algorithm. 3. New land/water mask products. 4. Change of format of global spatially-resolved data products. 5. Changes to some variable names. 6. Changes to file contents. 7. Latitude ordering changed from [90,-90] to [-90,90]. Documentation History 22/09/10 Document created 24/09/10 Correction to table of lakes (table 7) 22/03/11 Major revision to accommodate significant differences between v1.0 and v1.1 data products and additional v1.1 data products. Please see http://www.geos.ed.ac.uk/arclake/data.html for documentation for v1.0. 31/03/11 Averaging Methods section updated to describe v1.1.1 products Description of NICE data field updated. 15/04/11 Updated product descriptions to reflect removal of redundant variables and attributes. 17/01/14 Major revision to accommodate significant differences between v2.0 (and earlier) data products and v3.0 data products. Overview This document describes the data products released through the ARC-Lake project, funded by the European Space Agency. A number of different types of data product are available, from gridded observations on a lake-by- lake basis to global climatology. Data products derived from spatially complete reconstructions are available alongside those derived directly from the ARC-Lake observations. A summary of the possible variants is given in Table 1. Note that not all possible combinations of these variants are available: Variants Source Observations Reconstructions Coverage Per-lake Global Time Day Night Spatial Resolution 0.05° grid Lake-mean Temporal Averaging Type Climatology Time-series Temporal Averaging Seasonal Monthly Twice-monthly Daily Period Table 1. Overview of the types of data product available through ARC-Lake. ARC-Lake v3.0 data products include both lakes and reservoirs. For simplicity, the terms “lake” and “target” are used to refer to all types of water body. The structure and contents of these data products are described in detail in the following pages. Contents Version .................................................................................................................................................... 1 Release Notes .......................................................................................................................................... 1 Documentation History ........................................................................................................................... 1 Overview ................................................................................................................................................. 3 File Naming Convention ......................................................................................................................... 8 Summary of File Types ........................................................................................................................... 9 Averaging ............................................................................................................................................ 9 Unaveraged ..................................................................................................................................... 9 Averaged ......................................................................................................................................... 9 Source ................................................................................................................................................. 9 Observations ................................................................................................................................... 9 Reconstructions ............................................................................................................................... 9 Coverage ............................................................................................................................................. 9 Per-lake ........................................................................................................................................... 9 Global .............................................................................................................................................. 9 Spatial Resolution ............................................................................................................................... 9 Spatially-Resolved .......................................................................................................................... 9 Lake-Mean ...................................................................................................................................... 9 Temporal Averaging Type .................................................................................................................. 9 None ................................................................................................................................................ 9 Climatology ................................................................................................................................... 10 Time-series .................................................................................................................................... 10 Temporal Averaging Period .............................................................................................................. 10 Seasonal ........................................................................................................................................ 10 Monthly ......................................................................................................................................... 10 Twice-Monthly ............................................................................................................................. 10 Daily .............................................................................................................................................. 10 File Contents ......................................................................................................................................... 11 Colour Key ........................................................................................................................................ 11 Unaveraged – Per-Lake – Observations & Reconstructions ............................................................. 11 File Names .................................................................................................................................... 11 Dimensions ................................................................................................................................... 11 Variables ....................................................................................................................................... 11 Unaveraged – Global – Observations Only ...................................................................................... 13 File Names .................................................................................................................................... 13 Dimensions ................................................................................................................................... 13 Variables ....................................................................................................................................... 13 Averaged – Per-Lake ........................................................................................................................ 14 File Names .................................................................................................................................... 14 Dimensions ................................................................................................................................... 14 Variables ....................................................................................................................................... 15 Averaged – Global – Spatially-Resolved