Ash Study

[Two scientists standing in a burned field. One talking, one holding a spectrometer instrument.]

What we're doing in the field is were trying to calibrate an instrument that's going to be flying above us. It's a hyperspectral instrument.  It means to takes spectral data over probably 125 spectral channels...it's called a high map instrument.  It is being flown over all the different wildfires that burned by San Diego, the Harris fire, the Witch, the Santiago and also the Alamo fires.  So were at the Witch fire. This is actually our calibration site at the Witch fire and this is a field spectrometer that we're using to collect, let's say, ground truth for our calibration of a hyperspectral instrument. And the reason why we're doing this is we're trying to calibrate that hyperspectral data, because that instrument is going to fly around the whole burn area. And it's going to collect spectral data at many different wavelengths, sort of successive pictures at different wavelengths over the whole area, so we can look at the ash. The ash may not be distributed uniformly throughout all area. Some places there is more ash than others and what we're looking at for the biologists is how that ash is going to affect the aquatic life, they want to know when they ask is mixed in with the soil, how long the soil is going to take to recover so that it can support vegetation and growth again.

[Pointing at and around the spectrometer.]

This is the spectrometer. This is the heart of the instrument. This has actually three separate spectrometers inside of it. This is a communications cable that actually communicates with the computer. This is where all the spectral data gets stored. And this is the optic fiber, right here, and this actually has about 53 strands 57 strands of optic fiber that go back into the spectrometer and divide up the signal, the light signal comes through the opening right here to the two different spectrometers in the back.

[Both men are walking through the field demonstrating the spectrometer.]

With the the optic fiber we're going to walk and take measurements at the same time and record probably about 150 different spectral measurements systems so that we can spectrally characterize the field for the overflight. We want to know what that portion of land looks like so that we can use that to correct the data that is going to be collected by the high map instrument. In a burn situation like this, this is an emergency response situation, there are a lot of different components, different disciplines within USGS that are coming into play. Biologic, water resources, mapping, and also geologic division. So what were doing here is we're feeding information into that whole pool of researchers so that we can use all different talents to come up with a better picture of what's going on. The biologists will tell us how it affects wildlife. The geologists will help identify the ash component, and also will help with the calibration of the hyperspectral data. So were each lending our own expertise to helping...to do an emergency response so that we can figure out how this area is going to recover or even make suggestions on how it can recover sooner.