Airborne Snow Observatory and Distributed Hydrologic Modeling: Next Generation of Snowmelt Runoff and Operations Forecasting

Thomas H. Painter, Ph.D. Scientist NASA - Jet Propulsion Laboratory California Institute of Technology MS 233-306D 4800 Oak Grove Drive Pasadena, CA 91109

Tel: (818) 393-8226 (office) (626) 319-3111 (mobile) Email: Thomas.Painter@jpl.nasa.gov Web: aso.jpl.nasa.gov snow.jpl.nasa.gov

BIOGRAPHICAL SKETCH Thomas H. Painter, PhD, is a Scientist at the Jet Propulsion Laboratory/Caltech and a research professor at the University of California, Los Angeles. His areas of interest are snow hydrology, radiative impacts of light-absorbing impurities on snow and glacier melt, multispectral remote sensing and imaging spectroscopy, and solar system astrobiology. He received the PhD and MA in Geography from the University of California, Santa Barbara and the B.S. in Mathematics from Colorado State University. He was an Assistant Professor of Geography at the University of Utah, and Research Scientist at the National Snow and Ice Data Center. He is a member of the American Geophysical Union, the European Geosciences Union, International Glaciological Society, and Western Snow Conference. Dr. Painter is the President of the Cryosphere Focus Group of the American Geophysical Union and member of the AGU Eos Editorial Advisory Board. He is the Principal Investigator on the NASA/JPL Airborne Snow Observatory.

ABSTRACT Snow cover and its melt dominate regional climate and water resources in many of the world’s mountainous regions. However, we face significant water resource challenges due to the intersection of increasing demand from population growth and changes in runoff total and timing due to climate change. Moreover, increasing temperatures in desert systems will increase dust loading to mountain snow cover, thus reducing the snow cover albedo and accelerating snowmelt runoff. The two most critical properties for understanding snowmelt runoff and timing are the spatial and temporal distributions of snow water equivalent (SWE) and snow albedo. Despite their importance in controlling volume and timing of runoff, snowpack albedo and SWE are still poorly quantified in the US and not at all in most of the globe, leaving runoff models poorly constrained. Recognizing this need, JPL developed the Airborne Snow Observatory (ASO), an imaging spectrometer and imaging LiDAR system, to quantify snow water equivalent and snow albedo, provide unprecedented knowledge of snow properties, and provide complete, robust inputs to snowmelt runoff models, water management models, and systems of the future. The ASO is being evaluated during a multi-year Demonstration Mission of weekly acquisitions in each of the Uncompahgre River Basin (Upper Colorado) and the Tuolumne River Basin (Sierra Nevada) beginning in spring 2013. The ASO data will be used to constrain spatially distributed models of varying complexities and integrated into the operations of the O’Shaughnessy Dam on the Hetch Hetchy reservoir on the Tuolumne River. Here we present the first results from the ASO Demonstration Mission.

JPL Airborne Snow Observatory

Imaging snow water equivalent and snow albedo Principal Investigator: Thomas H. Painter, JPL/Caltech

Outline

Why the Airborne Snow Observatory?

What is the Airborne Snow Observatory?

How has it worked in practice?

Results from Demonstration Mission 1 (ASO-DM1)

When can we get the Airborne Snow Observatory to do all that we want?

Why ASO?

Snow gives most of the water

But there is a lot more to it

Elk Range, Colorado River Basin, April 2009

Senator Beck Basin, CO; Tmax 13-15 °C

Morteratschgletscher (Oerlemans, 2000)

What controls snowmelt?

New insight from obsUncompahgre River,

ColoradoUpper Colorado River Basin

Ordinate

Senator Beck Basin Study Area San Juan Mtns

Upper Colorado River BasinAbscissa Painter et al (in preparation)

Funding: NASA Interdisciplinary Science

Runoff rate vs Dust Absorption2005-2010

Runoff rate vs Temperature2005-2010

Forecasting

Dozier 2012

Snow Covered Area

MODSCAG 3 April 2002

Pillows and snow courses cover ~0.000000025 of the Tuolumne basin… or one forty millionth of the basin

Why not just satellites?!

They are definitely a part of the mix

However, they have fixed flight operations – so they cannot adjust to cloud cover or fly upon demand

Those with the frequency needed cannot provide the spatial resolution needed

THEY DO NOT GIVE US SWE!

Snow Water

Equivalent

Albedo

What is ASO?

Imaging Spectrometer0.35-1.05 μm

2 m spatial resolution from 4000 AGL

3D Scanning LiDAR1064 nm

1 m spatial resolution

Albedo

SWE

Uncertainty < 2%

Uncertainty < 5 cm

How does ASO work in practice?

Flight lines LiDAR composite

Point density

Tuolumne River Basin, Snow Density simulationiSNOBAL model, 3 April 2013

Mosaic of spectrometer

Spectrometer mosaic

3 May 2013

Imaging Spectrometer Products

ASO Results

TUOLUMNE BASIN

weekly

UNCOMPAHGRE BASIN

weekly

Snow Water Equivalent

(m)

SWETuolumne River Basin21 April 2013

Albedo

AlbedoTuolumne River Basin21 April 2013

Mt. Lyell Topographic

Mt Lyell (natural color)

Imaging spectrometer data draped on snow-on digital elevation surface.Seam expresses need for tomorrow’s update to lidar spatial calibration and spectrometer camera model.

2 April, 2013

Mt Lyell (SWE)

Results

ASO Results –

SWE

Tuolumne

Basin SWE declined from 218 to 42 TAF in 59 days

Inflow was 289 TAF, while melt was 203 TAF

Recharge, ET, and transient storage accounted for the difference

Melt rates varied based on solar input

Uncompahgre River Basin (above Ridgway Reservoir)

19 April 2013

Uncompahgre River Basin (above Ridgway Reservoir)

17 May 2013

Uncompahgre River Basin (above Ridgway Reservoir)

17 May 2013

Uncompahgre River Basin (above Ridgway Reservoir)

17 May 2013

Uncompahgre River Basin (above Ridgway Reservoir)

17 May 2013

All of this in < 24 hrsThe core of ASO is the supercomputing data analysis

Hydro Modeling Results

Tuolumne

Precipitation and temperature were forecasted from 6/1

Simulated and observed inflow are similar from 5/15 through 6/1, the forecast point

Modeled SWE (red) corrected by ASO SWE (blue)

Observed inflow much less than initial prediction

ASO-based forecast closer to observed

Reservoir operations were adjusted (draft reduced) after ASO forecast, HH reached the top of the gates, was full, and no water was lost to spill

Hydro Modeling Results

Tuolumne

What is next for ASO?We are working through the last technical

details of scaling to cover the Sierra Nevada and Upper Colorado River Basin

in a timely mannerWe are working partnerships with the

State of California, Colorado River Basin States, Department of Interior