Arctic haze

Transcription

[music] >> Jack Dibb, Platform Scientist: One of the places that has been shown to be warming faster than anywhere else on Earth is the Arctic. >> Jim Crawford, Program Manager: Given the recent loss of Arctic ice in 2007, which was unprecedented, it’s a fortuitous time for us to be here looking at climate change in the Arctic. We’re particularly interested in the atmospheric contribution to that. >> Hanwant Singh, Co-Mission Scientist: There’s a lot of pollution that is transported there. So our main goal is to see how it is getting transported, where it is coming from, and what impact it might have to the regional climate in the Arctic, which is also a climatologically very sensitive region of the Earth. [music] >> Jim Crawford, Program Manager: The NASA Tropospheric Chemistry program has flown these airborne missions for many years now, really two decades. But what brings us to the Arctic at this time is the International Polar Year. >> Jack Dibb, Platform Scientist: ARCTAS itself is the most ambitious airborne sampling that NASA’s ever done, but we’re also collaborating closely with the International Polarcat Campaign. And they will be bringing a whole lot of other international players to the party, including our colleagues from the U.S. >> Hanwant Singh, Co-Mission Scientist: We are putting together an international group to really study this system using all of NASA’s assets. Aircraft, satellites, models, everything we’ve got, to perform a really detailed and intensive study in the Arctic. >> Jim Crawford, Program Manager: So in the spring we’re looking at what’s been traditionally described as Arctic Haze. And this Arctic haze has components that come from pollution transport from mid-latitude locations. North America, Europe, Asia, Siberia, all of those locations, all lending some portion of what’s found up here in the Arctic this time of year. >> Jack Dibb, Platform Scientist: One question is how did it get to the Arctic in the first place and then what happens to it after it’s there. >> Jim Crawford, Program Manager: One of the more unique things about the Arctic chemically is that unlike other parts of the world where you have what we call a diurnal cycle, the sun rises and sun sets. In the Arctic you have a much longer time span over which you have a dark period in the winter and then the sun rises in the spring. During the winter many things can be transported to the Arctic, but they sort of sit and wait chemically for the sun to come. And since sunlight is the main driver of chemistry in the atmosphere, that becomes an important period to observe. >> Jack Dibb, Platform Scientist: There’s also speculation that the dirt and the black carbon that is in Arctic haze that is deposited just as the sun is coming up may actually change the albedo of the snow and hasten the melt season. As the Arctic warms it’s going to impact how the atmosphere is functioning, but there are a lot of reasons to think that changes in the atmosphere are contributing, are forcing, the Arctic warming. >> Jim Crawford, Program Manager: We’re not only looking at CO2, but clearly, methane, and CFC’s and ozone even more importantly. Ozone being a greenhouse gas that’s not emitted by pollution, but is created through the chemistry of pollutants as they’re transported to the Arctic. >> Hal Maring, Program Manager: In the summer campaign we are going to be looking particularly at what gets produced by forest fires. >> Jim Crawford, Program Manager: Over the past several decades, the intensity and frequency of boreal fire season has increased, and there are a lot of questions about whether there are feedbacks associated with climate and the increased intensity of fires. >> Hanwant Singh, Co-Mission Scientist: We will also be measuring a lot of aerosols and particles and their composition. >> Hal Maring, Program Manager: What’s of particular interest for us are the impact of those aerosols on radiation in the atmosphere. Do they reflect sunlight away from the Earth? Do they absorb sunlight and cause warming in the atmosphere? Do they cause warming in the atmosphere at a level above the Earth, and actually then, as a result cause cooling at the surface? >> Jim Crawford, Program Manager: It is true that while we’re up here, compared to other places, it does look very clean. But at the same time, with sensitive enough instrumentation, you can show clear signatures of impacts that can’t be explained by local conditions. So there is clear evidence of that pollution. >> Jack Dibb, Platform Scientist: Pollution is a transnational issue; that everybody lives downstream from somebody else. And certainly that is tied up with; many of these pollutants are also greenhouse gases or climate forcers. And so, it is, the Arctic is a very sensitive indicator of how interconnected the Earth is and how our activities are impacting it. >> Jim Crawford, Program Manager: Given the fact that the pollution is so far away and so distributed, it’s important for us to be able to see if from many different locations. What the planes are doing right now is they’re providing hundreds of observations that provide an important context to those longer-term observations that can only see the most important variables, but not necessarily all of the ones that are affecting change over time. [music]