Crysopheric and Polar Processes Seminar
Understanding the atmospheric drivers of Arctic sea ice variability – the role of past and future aircraft experiments
Dr. Sebastian Schmidt
This seminar will explore how aircraft observations can be used to study atmosphere-radiation-surface interactions in the Arctic. Although shortcomings in model predictions of sea ice and atmospheric parameters play out on different spatial and temporal scales, they cannot be addressed separately because the atmosphere and the surface interact through different mechanisms that depend on region, season, and prevalent synoptic regimes. One can argue that this is precisely the challenge for future Arctic experiments. Aircraft observations are not the immediately obvious choice for studying complicated interaction processes, especially when these manifest themselves on variegated scales or magnitudes. Fortunately, we have learned a lot from recent radiation science experiments where aircraft observations were synthesized with ground-based and satellite data within a modeling framework. When integrated in such a way, airborne measurements turn out to be a key component in an observational strategy that can access interaction processes with adequate detail. I will give examples of this emerging trend, discuss some of the lessons learned, and touch on new capabilities. Building on these, I will motivate a new experiment initiative with science questions that link Arctic clouds, atmospheric structure, surface conditions, radiation and precipitation. A central goal is to diagnose (and ultimately improve) the ability of different models to trace Arctic clouds throughout their lifetime in a way that is consistent with merged airborne, surface, and satellite observations. I will present an evolving strategy for capturing the various scale-dependent interaction processes with observational approaches inherited from prior experiments, and invite the audience to join in the discussion of the most relevant science questions.
Mapping burned areas using dense time-series of Landsat data
Dr. Todd Hawbaker and Dr. Melanie Vanderhoof
Hawbaker and Vanderhoof from the USGS in Lakewood, CO will be visiting to talk about their most recently published data product and discuss potential collaboration with CIRES/Earth Lab groups. Hawbaker will be giving a 1 hour lecture on the creation and validation of the fire product.
Abstract: Complete and accurate burned area data are needed to document patterns of fires, to quantify their drivers, and to assess the impacts on human and natural systems. Unfortunately, existing fire occurrence datasets are known to be incomplete. In response, we developed the Burned Area Essential Climate Variable (BAECV) algorithm that identifies burned areas in dense time-series of Landsat data and used it to map burned areas across the conterminous United States from 1984-2015. The resulting products were validated using independent data and have accuracies better than existing global fire datasets. The BAECV products also show patterns of fire that are not well characterized by existing fire occurrence datasets. We anticipate the BAECV products will be useful to studies that seek to understand past patterns of fire occurrence, the drivers that created them, and the impacts fires have on natural and human systems.