Earth & Sky

To see today’s current map of fire hotspots in the western U.S., please visit this link at the Fire Sciences Laboratory

Informative web links:

West faces a sixth year of epic drought: In some areas, conditions rival 1930s Dust Bowl (The Christian Science Monitor, April 27, 2004)

Transcript of our interview with Wei Min Hao:

WMH: I’m Wei Min Hao. I’m the project leader of the Fire Chemistry Unit at the Rocky Mountain Research Station, which is one of the research stations of the U.S. Forest Service. We are located in Missoula, Montana. And there are three projects in this Fire Sciences Laboratory. I have the Fire Chemistry Unit.

WMH: The research that my group focuses on how fire affects air quality, tropospheric ozone chemistry, and the global climate – because fires produce precursors for air pollutants and the greenhouses. By doing our research, we have also developed a new fire tracking system in 2002. We have installed a satellite receiving station in Missoula, Montana. And we can track fires four times a day for most of North America. We rely on the MODIS data from NASA’s TERRA and AQUA satellites. And so we can retrieve and process the original raw data and produce fire maps for the region covered in thirty minutes. So, within a period of four or five hours, we can produce a map covering most of North America. This is a very interesting progress for the fire monitoring, because we all know that we need to know where the fires are in almost the real time so we can develop a strategy for fighting fires and also investigating how fires will affect the safety of people and houses.

WMH: As we are approaching the peak of the fire season, which typically is in July-August in the western U.S., we will have a very busy summertime, because my staff has to work for 16 hours a day. So we take shifts to monitor the fires. We want to know where the fire locations are four times a day, which ranges from northern Canada to northern Mexico. And so this almost real-time monitoring becomes especially important in the western U.S. because of a severe drought in the last 7-8 years. So we’ve created many, many more fires than we used to have before. And then also, the fires tend to be big, very big, compared to many small fires historically. So in order to know where the fires are, and how the fire propagates, it is essential that we have a really updated knowledge. And for our research, we put our daily fire maps at our website. You can see the updated information.

WMH: Basically, the MODIS instrument on the TERRA and AQUA satellite monitors the thermal anamolie of each pixel, in 1 km by 1 km resolution. What I mean by thermal anamolie is, because in the data processing algorithms, we are looking for temperatures, in the pixels, that have a higher temperature than the background temperatures in the landscape. So if the temperatures are high, compared to the surrounding temperatures in the pixel, then we define it as a hotspot. Also, because we know the landscape, so we know what the vegetation is burned, and in this technology we can remove the potential stable hotspots like the stack, which also produce hotspots. But in our data processing we can remove these non-fire hotspots.

WMH: OK, there are two ways to look at the fire maps for individual fires. One is to draw a polygon of the hotspots, and then you define the fire perimeter. Another way is to use the infrared and the visible satellite data to define the burn scars, which should be black, in order to define a burned area.

WMH: For the small fires, it really affects the local community of the air quality. But for the mega-fires, you produce a lot of pollutants, and the fires last for weeks. So that you produce a huge smoke plume which can transport to long distance and downwind from the fires. There was evidence that fires in Canada can penetrate and propagate through the central U.S. The smoke plume from Mexico can propagate and dissipate across the southern borders and affect the southern states like Texas, New Mexico, Arizona. So this long-range transport is becoming a hot political issue, besides the air quality issue, because the other countries are producing smoke which affects another country’s air quality.

WMH: Actually, both in the fire management community, and also in the fire research scientific community, both have international collaboration because the major countries working on fire management include Canada, the U.S., Mexico, Australia, South Africa, and other countries. For scientific research on fire emissions and also the impact of the fires on air quality, it involves the U.S., Canada, many European countries, and some countries in South America and Africa. So, because when you burn a fire, the fire behavior, the combustion chemistry is all very similar. So the science and the technology can transport what we learn from one country and transfer to another country.

WMH: Each summer, how the fires extend, where the fires are, are very difficult to predict, because the driving force, or the determining factor is the weather. So it is very hard to predict what will really happen. And here probably, only a few weeks before the fire season of a particular region.

WMH: The satellites provide an excellent spatial coverage. And they cover wide areas, and you can update where the fire locations are four times a day. The traditional method relies on ground observation and lookout towers. From lookout towers, sometime we use aircraft to fly over a particular region to look where the fires are, where they extend. We use the satellite to compliment the ground-based and the aircraft monitoring of fires. But it does provide a broad view of where the fires are. It has demonstrated in the 2003 fire season in the northern Rockies, we have provided an excellent near-real time support to the multi-agency coordination group for the northern Rockies of August of last year.

WMH: To provide the fire location is very important because it gives the fire managers information to formulate the daily strategies for determining how they will allocate their resources, and also they will investigate the potential of areas that will be threatened by fires. There’s also one advantage to using the satellite to monitor fires. And that’s because the satellites can look through the heavy smoke and detect the hotspots of the fires. During the severe fire season, with heavy smoke, it gets very unsafe to fly aircraft, because of the low visibility. So the satellite has another advantage. Aerial reconnaissance will provide a higher spatial resolution.

WMH: This part of the work is funded by the Forest Service National Fire Plan in 2001. And in the spring of 2002 my group has set up a satellite receiving station. And we have been monitoring fires continuously, daily throughout 2002, 2003, and will continue through 2004. And we anticipate continuing to monitor fires for most of North America in the coming years.

WMH: What really surprised me is how much we can do with the satellite data, because in from the experience in 2003, we find that using the night-time detection of the hotspots, we can use this information to initialize the fire behavior model to predict the propagation of fires during the day. We can use the satellite data to develop airborne reconnaissance flight paths for the next evening. So there are a lot of the new technologies and new applications that we didn’t anticipate when the project started two years ago.

WMH: The National Interagency Fire Center will map the major fires in the U.S. using citation to fly over, to detect hotspots of the fire or the fire perimeters, normally around midnight because there’s a cooler background temperature. So it’s easier to detect the fire perimeters. This flight plan needs to be developed and set up by 2 o’clock in the afternoon, so they have 10 hours lead time to set the flight path. But if we updated the fire locations, or the fire perimeters at 2 o’clock in the afternoon, the best way to do it is to get it from the satellite image, which we normally acquire around noon time.

WMH: Hotspots basically are the fire locations, because at that particular location, the temperature is higher than the background temperature. So then, we call the fire location a hot spot. Because in the satellite imagery we see the higher temperatures. And we also display these hotspots in red in our satellite images on our website.

WMH: One hotspot has a 1-km by 1-km spatial resolution. But for the Hayman fire site, the total fire size at the end is about 500 sq. km, so there would be hundreds of hotspots for one particular large fire. And what we do is we track how the fire grows, so in other words we track how the number of hot spots and the spatial/temporal event as the fire grows daily.

WMH: I think that the difficulty is to validate the accuracy of the fire locations and the fire energy. We have spent a lot of time in the last two years to verify the fire locations by comparing the ground and area database collected by the Forest Service and other land management agencies. We find that the satellite data are very accurate in detecting fires. I think that the difficulty is to distribute to the use community, and because it’s a new technology, there are many new applications with limited resources. It is difficult and time-consuming to educate new users. And we are fortunate to work with the Northern Rocky Multi-Agency Coordination Center last fire season. It happens that the coordination group is located next to our building, so we can have a really direct service with them. But for other places it will be more difficult. So I would like to see a more coordinated effort to distribute this information of this new technology for the field users.

WMH: I think for the public to go to this website is very, very important. Because, for them they can actually see where the fires are near their neighborhood in their state or even to plan their vacation during the summer. We do have the fire map on the website, and it can give you a very good view.

WMH: I need to let you know that our website is http://www.firelab.org/rsl, it stands for Remote Sensing Laboratory.

WMH: We don’t know yet about this year, but we do see a trend in the last four or five years or more and more fires, more and more bigger fires, in the western U.S. So if not this year, I anticipate that in the next 1-2-3 years we will see a lot of fires again in the western U.S.

WMH: We don’t track the recovery from fires. But in my agency, there are different groups that track the area burned, the fire severity of the burned areas. The goal more is to rehabilitation of the burned area and also study how the fire affects the ecosystem.

WMH: I’d really like the public to know there’s a really new modern technology that can give us not only the scientific fire management community to use. Also for the general public to use and understand how fire affects their own community.

WMH: We have this one station to track fires, but there are probably 80 in the world. So our technology we develop for our laboratory can be applied for real-time monitoring globally. So I’m attending a conference in China to give a seminar on that.

WMH: China is actually, they had huge wildfires in Manchuria, or now these days you don’t call Manchuria – eastern China and the bordering Russia. Since then China has stricter fire control, so that when you go into the forested area you have to be searched to make sure that you don’t have matches. And then also they developed earlier satellite monitoring techniques too. And so China is controlling fires very well.

WMH: Different countries have different policies and approaches. From what I can tell, in the tropical countries, fires are more for the land-uses, for clearing forested areas and for agriculture, for creating agricultural areas. So in the tropics, where 80% of the fires are, mostly it’s for human purposes. Wildfires in the U.S., probably half are human caused and half by lightning. However, one of the most interesting areas of fires is in Russia. You can see a lot of the fires in eastern Siberia along the Trans-Siberian railway. So all the fires happen mostly along the railway track. People toss out a cigarette. And, also, more people. In the last 10 years, which you see from the satellite, there are more and more fires in Russia because they don’t have enough resources to fight fires.

The following person was interviewed for today’s program. Our thanks to:

Wei Min Hao, Ph.D.
Project Leader
USDA Forest Service
Fire Sciences Laboratory
Missoula, MT