For a better understanding of how much water is contained in each winter’s snowfall and how much will be available when it melts in the spring, NASA has launched a seasonal campaign called SnowEx in 2016-17
SnowEx is a five year program initiated and funded by NASA to address the most important gaps in snow remote sensing knowledge. It focuses on airborne campaigns and field work, and on comparing the various sensing technologies, from the mature to the more experimental, in globally-representative types of snow.
Reasons to start the program
- Despite snow’s unique importance to the global Earth system, no single satellite-borne sensor has been demonstrated to accurately measure all of the planet’s snow water equivalent.
- To understand the time and space variation in the snow’s energy and mass balances along with the extensive feedbacks with the Earth’s climate, water cycle, and carbon cycle, it is critical to accurately measure snowpack.
- NASA’s overall target is optimal strategies for mapping global snow water equivalent (SWE) with remote sensing and models leading to a Decadal Survey “Earth System Explorer” mission
Main Aims and Objectives
The project aims to quantify and compare capabilities and limitations of traditional and newer snow estimation techniques across a range of environmental conditions, with an emphasis on articulating satellite remote sensing strategies and requirements.
The goal is to address the most important gaps in our snow remote sensing knowledge, and thus lay the groundwork for a future snow satellite mission.
It uses airborne measurements, ground measurements and computer modelling.
- The Airborne campaign will
- Fly RADAR and LIDAR (light detection and ranging) to measure snow depth,
- Microwave radar and radiometers to measure SWE,
- Optical cameras to photograph the surface,
- Infrared radiometers to measure surface temperature, and
- Hyperspectral imagers for snow cover and composition.
- Ground teams will measure
- Snow depth and density,
- Accumulation layers,
- Snow temperature, wetness and snow grain size — the size of a typical particle.
- This year, real-time computer modelling will be integrated into the campaign as well.
- Application of process-based snow models and data assimilation experiments will provide further insights into optimal strategies and concepts for monitoring global snowpack in a future mission.
The geographical focus of SnowEx is proposed as North America which contains the six broad snow climate categories
- Tundra (alpine or Arctic),
- Taiga (Boreal forest),
- Warm (temperate) forest
- Maritime,(Pacific Northwest Region)
- Prairie, and
Benefits of SnowEx
- The high variability of global snowpack conditions requires a systematic investigation of sensor capabilities and sensitivities across a range of environments and spatial and temporal scales.
- SnowEx will provide key insights into optimal strategies for mapping global SWE with remote sensing and models, which will enable a competitive proposal for a Decadal Survey “Earth System Explorer” mission.
- Provide unprecedented knowledge of snowpack quantity and how it varies over seasonal and annual scales across the globe, thereby transforming watershed and ecological management and climate monitoring.
- A future snow satellite mission, informed by SnowEx experiments, would enable estimation of the critical snow properties on a global scale