CaWarmingViz
The link below lets you download a java program I wrote that provides a
3d view of the California landscape, with representations of statewide April
snowpack and summertime San Francisco Bay salinity superimposed. The snowpack
and salinity fields change over the course of 100 years, representing the effect
of a climate change scenario on these quantities.
The inspiration for this program was the fact that current global climate models provide a range of predictions of temperature and precipitation change over California in the coming century. Rather than considering the implications of a given GCM's simulation, "CaWarmingViz" lets the user specify a particular rate of warming (from +1 deg C to +6 deg C per century) and a particular precipitation change (from -30% to +100% per century), and watch the impacts of the chosen scenario on snowpack and salinity unfold as the animation plays out over the next 100 years.
Given some caveats (below), this program provides a useful tool for gaining intuition about the nature of potential hydrologic changes in California, and the dependence of these changes on temperature and precipitation trends in this century.
The values depicted in this program were derived by running the California Watershed Model (a Statewide hydrologic model with a 4km resolution), coupled with the Uncles-Peterson Estuary Model, multiple times with different values of temperature and precipitation change. For each grid cell in each model a multivariate piecewise linear regression was performed for the resulting snow and salinity values against the precipitation and temperature change values. The resulting parameterizations are used to generate the values shown in CaWarmingViz.
The program has room for improvement, including:
-- the UI is rather crude, since I'm not very good at java layouts yet.
-- There is no color legend for the snow and salinity color maps. For snow,
blue is 500mm SWE, red is ~0mm. For salinity, orange is ~34 psu and blue is
0 psu.
-- Plenty of other things, including the often-suggested separate window showing
the Bay as a closeup.
Also, the represented impacts are themselves uncertain, and important caveats
should be kept in mind:
-- These results assume that the temperature and precipitation changes are
uniform over all of California, when in fact there is likely to be considerable
heterogeneity in these changes, such as a dependence on altitude.
-- The salinity changes reflect an assumption of no mitigation efforts. Management
adaptations will undoubtedly result in a different picture than that shown by
CaWarmingViz, but the impacts shown here can be taken to represent the effects
those adaptations must be designed to mitigate.
-- see N. Knowles and D. Cayan, 2002. "Potential effects of global warming
on the Sacramento/San Joaquin watershed and the San Francisco estuary"
Geophysical Research Letters, 29(18) for more information.
System Requirements:
This program uses ~140MB RAM, so your computer should have at least 512MB,
depending on how much your system takes up. A decent graphics card would help
(with DirectX/OpenGL acceleration), as would a fast processor (at least 800MHz
I'd guess).
You'll DEFINITELY need to have the following installed:
1) Java Runtime Environment (JRE), available at:
http://java.sun.com/j2se/1.4.1/download.html
(just the JRE; you don't need the SDK)
2) Java 3D Runtime (OpenGL or DirectX, either should work), at:
http://java.sun.com/products/java-media/3D/download.html
3) Java Advanced Imaging Runtime ("JRE Install" version), at:
http://java.sun.com/products/java-media/jai/downloads/download.html
(you will need to register with Java Developer Connection to get this one.)
Instructions:
If your system meets the above requirements, or if you have no idea but
want to give it a shot anyway, download the zip file using the link at the bottom
of this page, and extract to your favorite directory.
Before you continue, please know that I take no responsibility
for any problems running this program causes you!
I've only tested it on 4 computers, and it has done no harm yet!
OK, now double-click on the CaWarmingViz.bat file and the program should start
up. On my machine it takes about 15sec to start up; your time might differ.
A little window with California in it should eventually appear. If it does,
it works!
***
Remember what you're seeing-- the snow color field represents April-averaged
snowpack in the year indicated on the bottom slider, and the salinity color
field represents summer (JAS) average salinity in the same year. These times
were chosen because April is typically the apex of annual snowpack accumulation,
and loss of snowmelt runoff due to warming leads to reduction in spring/summer
estuarine inflows, resulting in an increase in summertime Bay salinities. Again,
see the Knowles and Cayan article (above) for more information.
***
To use the program:
1) Click on California to give the inner panel keyboard focus.
2) Press 'f' to toggle fullscreen mode so you can actually see something, or just resize the window if you don't want to (or can't) use fullscreen.
3) Use the left and right sliders to set the temperature and precipitation changes.
4) Press the 'Play' button (at the top of the screen) to set it in motion.
5) Use the the left, middle, and right mouse buttons to tilt, zoom, and move parallel to the ground, respectively. When you do this, the animation will freeze until you release the button. You can also press 'Pause'.
6) Press 's' to toggle the snow colormap from the rainbow map to a more realistic (but less informative) white. The change will not go into effect until the time is changed again, either by pressing 'Play', or changing the time using the time slider at the bottom of the screen.
7) Press 'q' to quit. Again, for keyboard input to work, click on the image of California first to give the center panel keyboard focus.
That's about it. Email me with questions or suggestions.