National Aeronautics and Space Administration

National Climate Assessment

NASA National Climate Assessment (NCA) Activities

NASA Indicators Solicitation Proposals

Development and Testing of Potential Indicators for the National Climate Assessment

Lead PI and Center: Simon Hook, Jet Propulsion Laboratory
Title: Inland Water Temperature: An Ideal Indicator for the National Climate Assessment

NASA is a significant contributor to the U.S. National Climate Assessment (NCA), which is a central component of the 2012-2022 U.S. Global Change Research Program Strategic Plan. The NCA has identified the need for indicators that provide a clear, concise way of communicating to NCA audiences about not only the status and trends of physical drivers of the climate system, but also the ecological and socioeconomic impacts, vulnerabilities, and responses to those drivers.

We will use existing thermal infrared satellite data in conjunction with in situ measurements to produce water temperatures for all the large inland water bodies in North America to be used as an indicator for the NCA. Recent studies have revealed significant warming of inland waters throughout the world. The observed rate of warming is - in many cases - greater than that of the ambient air temperature. These rapid, unprecedented changes in inland water temperatures have profound implications for lake hydrodynamics, productivity, and biotic communities. Scientists are just beginning to understand the global extent, regional patterns, physical mechanisms, and ecological consequences of lake warming. We will assemble and synthesize records of lake temperature from both in situ and remote sensing data sources to understand the interactions between lake hydrodynamics and ecology throughout the full water column.

These synthesized records of lake temperature are ideal for communicating the state of the climate to the public, decision makers, and academia. Our synthesized product will directly support multiple sections of the 2013 National Climate Assessment report, providing information on the scientific basis for climate change as well as how different sectors and geographic regions are being affected by climate change. Information on how large inland water body temperatures are changing cuts across the different regions and sectors and will help enable a more integrated understanding of the changes that are taking place. 

As part of our earlier studies we have collected the thermal infrared satellite data from those satellite sensors that provide long-term and frequent spaceborne thermal infrared measurements of inland waters including ATSR, AVHRR, and MODIS and used these to examine trends in water surface temperature for approximately 100 of the largest inland water bodies in the world. The primary objectives of this work are (1) Extend the temperature time-series to all of the North American inland water bodies that are sufficiently large to be studied using 1km resolution satellite data for the last 3 decades; (2) relate changes in the thermal behavior of the water bodies to changes in surface air temperature data; (3) compare the regional trends in water surface temperature derived from these observations to those in the CMIP5/IPCC model simulations/projections; (4) predict future changes in inland water body surface temperatures based on comparisons with the models and (5) summarize the data using ecologically relevant indicators that are meaningful to the general public, and make it available for the National Climate Assessment writing teams.

We have the necessary remote sensing datasets in-house and collaborate with a broad network of scientists who collect in situ lake temperature measurements. The satellite-based datasets include the entire archive for MODIS, ATSR and AVHRR over N. America. Our AVHRR archive includes the 4-km Global Area Coverage (GAC) and 1-km Local Area Coverage (LAC) data. We have developed a consistent processing methodology specifically for deriving the surface temperature of inland waters that will allow the entire long-term data record to be processed in a consistent manner (including error analysis) and have developed a set of automated calibration and validation sites to verify the satellite data and surface temperature retrievals.