Remote Sensing for Climate Change Effect on Lake Tahoe. Shobha Sriharan Professor of Environmental Science Virginia State University

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1 Remote Sensing for Climate Change Effect on Lake Tahoe Shobha Sriharan Professor of Environmental Science Virginia State University

2 Table of Contents Lake Tahoe s Climate Issues Discussion on the issues that plague Lake Tahoe Applications of ERDAS LANDSAT Satellite images Understanding Supervised Classifications Analysis of image classifications (What the data tells us)

3 On Average, below 900 feet, the Lake s temperature maintains at 40 F and surface water averages 41.9 F. However, over the last 10 years the lakes temperature has risen, on and below the surface, making Lake Tahoe s water almost 1.5 to 2 degrees Fahrenheit warmer monthly Temperature Fluctuations

on Lake Tahoe s water surface, which in turn can have vast effects on

4 Effect of Temperature Fluctuations Due to this temperature change, algae and invasive plant species grow faster due to ideal warmer temperatures on Lake Tahoe s water surface, which in turn can have vast effects on marine life, and kill certain animals and or destroy their main food sources.

Warmer temperatures also cause an earlier spring time snow melt.

5 Excess Rain and Snow Fall Decreasing Rain fall levels are at a steady increase in the Lake, while snow fall is decreasing. Warmer temperatures also cause an earlier spring time snow melt. 65% of Lake Tahoe s water comes from water melted by snow, with less snowfall, there is less water that flows into the Lake. Warmer temperatures decreases snow fall

Effects of Excess Rain Lake Tahoe s water is 99.994% pure, in turn boasting the title of one of the purest lakes in the world.

6 Effects of Excess Rain Lake Tahoe s water is % pure, in turn boasting the title of one of the purest lakes in the world. Distilled water is % pure. Therefore, increased flooding causes severe damage downstream also increase erosion and run-off.

7 Mixing of Sedimentation Layers Lake Tahoe s biggest issue is warmer water temperatures The colder layers on bottom, gets warmer as water rises

8 Effects of Mixing of Sedimentation Layers This issue causes deep water mixing of layers which: decreases the coldest layer level of oxygen causing a dramatic shift in food chain

9 Applications of ERDAS-Imagine 13.0 A detailed analysis of Lake Tahoe s Snowfall monitored over a period of every four years starting with 2004, 2009, and ending in 2014

10 Methodology Explained ERDAS imagine 13.0 software allowed us to depict the effects of climate change on Lake Tahoe, by way of displaying the decrease in snowfall. ERDAS uses bands, colors, to differentiate between classes, in this case, 6 classes: -Water (dark blue), Snow (light blue), Developed Land (purple), Rocks and Soils (tan), Vegetation (light green) and Forests (dark green). -Each class was specifically identified based on the images taken from LANDSAT 8: Years, 2004, 2009, and Each of these images were used to create a Supervised Classification or color-coded image for each year. 150 Training points were used to identify each class and then condensed into the five classes. The resulting images, clearly display a serious decrease in snowfall levels on the mountains and streams that flow into the lake due to the warmer weather.

11 The large light blue or CYAN color represents a large area surrounding the lake as snowfall with a varying degree of forests and vegetation, yet not greater than the area covered in snowfall. Note that the LANDSAT image was taken in November, 2004 Supervised Classifications of Images LANDSAT 8 Nov Comparison 2004, 2009, and 2014 ERDAS Imagine Supervised Image

12 ERDAS Classifications: 2009 Comparison LANDSAT 8 Nov ERDAS 11 Supervised Image In 2009, we see two things; an increase in vegetation and a smaller area of light blue snowfall. As stated before, increased rainfall, and less snowfall increases, the vegetation population within the area increases. Also note the smaller dark blue streams and ponds within the image.

a drastic decrease in light blue in the area, and also noting the drastic

13 ERDAS Classifications: 2014 Comparison LANDSAT 8 Oct ERDAS 11 Supervised Image In the 2014 image in comparison to 2009, we see a drastic decrease in light blue in the area, and also noting the drastic increase in vegetation. The small dark blue stream and pond areas, are no longer present orvisible on the image.

14 Conclusion Increased temperatures has decreased snowfall Increased rainfall and increased vegetation Also note, if you look closely at the lakes edges, a thin tan layer lines, it which could suggest lower water levels.

15 Understanding Lake Tahoe s Snowfall Levels and Importance

16 Conclusions Drawn Snowfall has drastically decreased from and has continued to do so The area surrounding the lake has experienced an increase in rainfall and vegetation The lake s water level is decreasing.

Thermal / Solar. When air is warmed it... Rises. Solar Energy. Evaporation. Condensation Forms Clouds

Thermal / Solar. When air is warmed it... Rises. Solar Energy. Evaporation. Condensation Forms Clouds Thermal / Solar Light from the Sun is transformed into what type of energy when it hits Earth's surface? Rises When air is warmed it... Solar Energy Water moves through the water cycle using what type