A Notional Airborne Science Research Strategy for NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) Fri, May 27, 16 This document expresses the opinions of the ABoVE Airborne Science Working Group and other interested parties. It does not represent the views of NASA. ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM Executive Summary: This document explores possible integrated airborne science research strategies for NASA’s Arctic Boreal Vulnerability Experiment (ABoVE). ABoVE airborne research will link field-based, process-level studies with geospatial data products derived from satellite remote sensing, spanning the critical intermediate space and time scales that are essential for a comprehensive understanding of scaling issues across the ABoVE Study Domain and extrapolation to the pan-Arctic. ABoVE airborne campaigns can provide remote sensing data with higher spatial and temporal resolution than available from satellite sensors as well as measurements that are not currently available from space. ABoVE airborne campaigns provide unique opportunities to validate satellite data for northern high latitude ecosystems, develop and advance fundamental remote sensing science, and explore and exploit new scientific insights from innovative sensor combinations. ABoVE is driven by the question: How vulnerable or resilient are ecosystems and society to environmental change in the Arctic and boreal region of western North America?” To address this overarching question, research during ABoVE is organized around six Science Themes that represent critical aspects of Arctic and boreal social- ecological systems: society, disturbance, permafrost, hydrology, flora and fauna, and carbon biogeochemistry. ABoVE airborne campaigns must coordinate timing, flight lines, sensor suites, etc to maximize scientific benefit and ensure delivery of critical data over ABoVE field investigations. The size and ecological complexity of the ABoVE experimental domain further complicates the development an integrated airborne remote sensing research strategy. ABoVE envisions major airborne campaigns in 2017 and 2019 with the potential for less comprehensive bridging activities in 2018. The strategy involves Foundational Measurements made with the NASA facility instruments UAVSAR and AirMOSS on the G-III and LVIS, AVIRIS-NG, HyTES and PRISM on the ER-2 (or alternate platform configurations). These will provide domain-wide sampling and coverage of ABoVE field sites. Additional measurements can be made by other sensors with an emphasis on higher resolution coverage over specific field sites or portions of the experimental domain. The strategy will seek to leverage complementary NASA airborne activities such as ICEBridge and SnowEx, pre-launch airborne acquisitions for NISAR, HyspIRi and ASCENDS, as well as activities sponsored by partner agencies. Coordination with ongoing or planned Canadian airborne remote sensing (eg lidar-based boreal forest inventories) would be a key aspect of this strategy. Page 2 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM Table of Contents EXECUTIVE SUMMARY: ........................................................................................................................ 2 1 INTRODUCTION & ABOVE STUDY AREA ................................................................................. 4 2 SCALING ISSUES & A STRATEGY FOR SAMPLING THE ABOVE DOMAIN ........................ 5 3 FLIGHT LINES FOR ABOVE FOUNDATIONAL AIRBORNE MEASUREMENTS ................. 7 3.1 THE ALASKAN CIRCUIT ................................................................................................................................ 9 3.2 THE CANADIAN CIRCUIT ........................................................................................................................... 12 3.3 THE BOREAL FOREST AND ARCTIC TUNDRA TRANSECTS .................................................................. 15 3.4 SUPPLEMENTAL FLIGHT LINES ................................................................................................................ 15 4 ABOVE FOUNDATIONAL AIRBORNE MEASUREMENTS .................................................... 20 4.1 MULTI-FREQUENCY RADAR: UAVSAR & AIRMOSS .......................................................................... 21 4.2 WAVEFORM LIDAR: LVIS ....................................................................................................................... 25 4.3 HYPERSPECTRAL IMAGERY: AVIRIS, HYTES & PRISM .................................................................... 26 4.4 EXPLOITING MULTI-SENSOR OBSERVATIONS ....................................................................................... 30 4.5 FOUNDATIONAL MEASUREMENT CAMPAIGN TIMING ......................................................................... 30 5 FOCUSED AIRBORNE MEASUREMENTS ................................................................................. 31 6 INTEGRATING ABOVE PARTNERS INTO THE AIRBORNE SCIENCE STRATEGY ........ 31 6.1 NASA AIRBORNE CAMPAIGNS & OPPORTUNITIES .............................................................................. 31 6.2 US PARTNER AIRBORNE CAMPAIGNS & OPPORTUNITIES .................................................................. 34 6.3 CANADIAN AIRBORNE CAMPAIGNS & OPPORTUNITIES ...................................................................... 36 6.4 OTHER PARTNERING OPPORTUNITIES ................................................................................................... 37 7 SATELLITE SENSOR SYNERGIES ............................................................................................... 40 8 CASE STUDIES ................................................................................................................................ 41 8.1 WILDLIFE & ECOSYSTEM SERVICES ........................................................................................................ 41 8.1.1 Snow & Ice Properties ...................................................................................................................... 41 8.1.2 Fine-scale Vegetation Structure .................................................................................................. 42 8.2 ARCTIC-BOREAL VEGETATION STRUCTURE AND DISTURBANCE ...................................................... 43 8.2.1 Fire & Topographic Change in Boreal Forests ...................................................................... 43 8.2.2 Boreal Ecosystem Dynamics & Carbon Balance ................................................................... 44 8.2.3 Fire Disturbance & Post-fire Recovery in Boreal Forests .................................................. 45 8.2.4 Challenges for Understanding and Managing the Canadian Boreal Forest ............. 46 8.3 TOPOGRAPHIC CONTROL OF HYDROLOGY-PERMAFROST INTERACTIONS ....................................... 48 8.3.1 Thermokarst & Permafrost Degradation ................................................................................ 48 8.3.2 Inundation, Surface & Sub-surface Hydrology ...................................................................... 49 8.3.3 Active Layer Thickness & Permafrost Physical State .......................................................... 50 8.3.4 Active Layer Thickness & Permafrost Physical State .......................................................... 51 8.3.5 ArcticDEM Reference Elevation Dataset Requirements .................................................... 52 8.3.6 Airborne Electromagnetic (AEM) Surveys .............................................................................. 54 8.4 LINKING ABR CARBON CYCLING AND VEGETATION DYNAMICS ....................................................... 55 8.4.1 Arctic-Boreal Carbon Cycle Dynamics ....................................................................................... 55 8.4.2 Characterizing Biogeochemical Drivers of ABR Carbon Cycle Dynamics .................. 57 9 REFERENCES ................................................................................................................................... 60 Page 3 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM 1 Introduction & ABoVE Study Area NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) is planned to be a 9- to 10- year field campaign sponsored by the Terrestrial Ecology Program focused on a large-scale study of environmental change in the Arctic and boreal region of western North America and its implications for social-ecological systems. ABoVE science is driven by the question: How vulnerable or resilient are ecosystems and society to environmental change in the Arctic and boreal region of western North America?” To address this overarching question, research during ABoVE is organized around six Science Themes that represent critical aspects of Arctic and boreal social- ecological systems: society, disturbance, permafrost, hydrology, flora and fauna, and carbon biogeochemistry. A detailed explanation of ABoVE’s scientific questions, objectives, and their motivation is provided in the ABOVE CONCISE EXPERIMENT PLAN <http://above.nasa.gov/acep.html>. Airborne science research is an important element of ABoVE. Airborne measurements have the potential link field-based, process-level studies with geospatial data products derived from satellite remote sensing, spanning the critical intermediate space and time scales that are essential for a comprehensive understanding of scaling issues across the ABoVE Study Area and extrapolation to the pan-Arctic. The ABoVE Study Area includes most of northwestern North America west of Hudson Bay and north and east of the coastal mountain ranges: Alaska, the Yukon and Northwest Territories (Fig 1). It encompasses the variability in the key land surface features that are both unique to Arctic and boreal ecosystems in North America as well as being representative of the larger Northern High Latitude region. • The Core Study Region captures the regional- scale variations in surface and atmospheric conditions necessary to address ABoVE science questions and objectives. It includes landscapes and ecoregions that are rapidly changing in complex ways as well as others that are not yet changing – a combination that Fig 1. The ABoVE study domain showing the Core and Extended allows for studies on Study Regions as well as the location of field sites operated by the both vulnerability and ABoVE Science Team. For more details and other maps, see resilience. http://above.nasa.gov/geospatial_map.html Page 4 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM • The Extended Study Region borders the Core Study Region, which allows for studies focused on a subset of important changes that are not occurring in the Core Study Region (for example, insect outbreaks and forest dieback in the southern boreal forest). The Extended Study Region includes areas where research can focus on environmental conditions that might characterize those in the Core Study Region in the near future. 2 Scaling Issues & A Strategy for Sampling the ABoVE Domain Understanding the vulnerability and resilience of the socio-ecological systems in the ABoVE domain requires knowledge of ecosystem state properties, environmental controls, processes and dynamics across multiple space and time scales. The science questions, remote sensing and monitoring tools, and integration and modeling tools used by ABoVE researchers will necessarily vary with the space and time scale(s) under consideration. Additionally, we expect the dominant processes and controls to vary across scales and for emergent properties to manifest themselves at larger space and time scales. Microtopography controls many aspects of ecosystem, permafrost and hydrologic dynamics at site to local scales (< 1 m to ~100 m). Landscape scale (100 m to 10 km) dynamics shift to the consideration of lakebed history, habitats, disturbance patterns and small watersheds. Meso- and regional-scale (10 km to 1000 km) dynamics reflect the characteristics of ecoregions, bioclimatic zones and their gradients. Sampling across time scales from hours to centuries is also essential for ABoVE science and provides unique challenges. Processes that occur on time scales much longer than the 10-year duration of ABoVE – such as fire recovery, shrubby encroachment, thermokarst and permafrost degradation, peatland bog-fen evolution, etc. – may be studied through sampling known chronosequences or by using space for time trades (eg using the Seward Peninsula as a proxy for a future North Slope). Hourly, daily, seasonal, annual and interannual time scale sampling will also be key to enabling ABoVE researchers to characterize fundamental processes, the differences between pulse and push forcings, and abrupt, discontinuous state changes due to disturbance events. A key challenge for ABoVE researchers will be to develop models that accurately integrate the range of data acquired from field studies, airborne measurements, and satellite remote sensing. Approaches that enable both accurate upscaling and downscaling of ecosystem dynamics across the range of space and time scales of interest to ABoVE has to date proven elusive [Vörösmarty et al., 2010]. The ABoVE airborne science sampling strategy should therefore deliver data that span the space and time scales of data acquired at ABoVE field sites and remote Page 5 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM sensing observations returned from satellite instruments. The strategy must also deliver data that challenge models, particularly their scaling properties, and enable their improvement. The strategy must also sample space, time, and biogeophysical gradients across the vast and diverse ABoVE Study Area. The ABoVE Science Team developed a multi-pronged strategy to address these requirements • Foundational Airborne Measurements will deliver cross-cutting remote sensing data from UAVSAR, AirMOSS, LVIS, AVIRIS-NG along Alaskan and Canadian circuits that sample critical ecosystem, vegetation, climatic regions and gradients to characterize landscape to regional scale properties and dynamics across the ABoVE domain. Supplemental Flight Lines extend the hierarchical spatial sampling of these transects to southwestern Alaska, the Canadian High Arctic, and the BERMS/BOREAS study areas. • Focused Airborne Measurements will complement the Foundational Measurements by delivering high spatial and temporal resolution data for smaller spatial domains within the ABoVE Study Area. Focused Airborne Studies may be concentrated in the areas surrounding ABoVE field sites and at the intersection points of major regional scale airborne transects, provide airborne data acquisitions along the portions of the Foundational Measurement Flight Lines made with instruments that complement the Foundational Measurements, and/or provide greater space-time sampling coverage than the Foundational Measurements. Airborne in situ sampling of carbon dioxide, methane, carbon monoxide and other trace gases for the determination of local to regional scale surface-atmosphere fluxes will be essential to link remote sensing and field measurements of processes driving Arctic-boreal carbon dynamics. • Contributed Airborne Measurements from NASA and ABoVE partners will integrated into the broader airborne strategy so as to optimize their benefit to ABoVE science. Contributed Airborne measurements may include data acquired in the ABoVE domain by current or planned NASA airborne campaigns (e.g. ICEBridge, SnowEx, SMAPVEX), the NEON Airborne Observatory, NOAA (e.g. Snow Surveys, Greenhouse Gas Sampling), DOE (e.g. NGEE-Arctic, Atmospheric Radiation and Monitoring Airborne Observatory), etc. The Foundational Airborne Measurements provide a framework for investigating domain-wide science questions while the Focused Airborne Measurements allow more detailed probing of process-level questions. Contributed Airborne Measurements will be exploited to augment ABoVE-funded efforts. Together, these approaches provide a flexible, cost effective means for maximizing the science return from ABoVE airborne campaigns. Page 6 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM 3 Flight Lines for ABoVE Foundational Airborne Measurements Flight lines for ABoVE’s foundational remote sensing measurements span the Core Study Region (Fig. 2). The transects feature intersection points at key infrastructure and field experiment sites, providing opportunities to link regional scale airborne Fig 2. Flight lines for ABoVE’s foundational airborne measurements (solid lines) sample This figure has been updated from the May 11th, 2016 version. important north-south and east-west gradients within the Core Study Domain. The Alaska circuit connects nexus points 1-2-3-4-5 and the Canada circuit connects nexus points 5-6-7. Supplemental flight lines (dashed lines) expand coverage into the High Arctic and the Extended Study Region (points 8 -14) observations with detailed studies from airborne observations focused on higher space-time resolution (Table 1). Supplemental flight lines offer the potential to expand airborne remote sensing coverage into the Canadian High Arctic and the Extended Study Region. The Foundational Measurement flight lines consist of a series of north-south and east-west transects that may be executed in 2 basic flight patterns. Both circuits can base out of Fairbanks, simplifying operations and logistics. • The Alaskan circuit features two north south transects: the Western North Slope – Bering Tundra/Seward Peninsula – Bering Taiga/Yukon-Kuskokwim Delta transect (points 3-2-1) and the Dalton Highway transect (points 4-5). These are connected via east-west transects that cover the transition from the Page 7 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM boreal interior to the Bering taiga (points 5-1) and sampling across the North Slope Arctic coastal plain (points 4-5). • The Canadian circuit features extended east-west transects cutting across the Alaskan boreal interior to the taiga plain near the Mackenzie Delta (points 5-6) then follows the northern treeline along the tundra/taiga ecotone (points 6-7) before returning across the upper Mackenzie River basin tiaga plains and across the boreal cordillera to Fairbanks (points 7-5) Table 1. ABOVE Foundational Measurement Transect Intersection Points Point Name/Airport Field Study Assets 1 Bethel, AK ABLE, CARVE historical data; tall tower candidate (PABE) location; YK Delta field sites (Frost) 2 Nome (PAOM) NGEE-Arctic flux towers and field sites at Teller, Kougarok, Council; fire sites (ABoVE PIs) 3 Barrow, AK NGEE-Arctic flux towers and field sites; Oechel flux (PABA) towers; NOAA surface site; DOE/ARM North Slope Alaska site; CALM sites; BLM AIM sites 4 Deadhorse, AK DOE/ARM Oliktok Point site; long term vegetation (PASC) measurement sites; Dalton Highway corridor 5 Fairbanks AK UAF; BNZ LTER; USFS plots; etc (PAFA) 6 Inuvik NT (YEV) Taiga Plains Research Network flux towers; Env Canada tower; Mackenzie Delta permafrost sites 7 Yellowknife, NT Fire studies (Multiple ABoVE PIs); Env Canada tower; (YZK) Tundra-taiga ecotone (Eitel), etc. 8 Cambridge Bay CHARS and associated field sites; Env Canada tower (YCB) 9 Resolute Bay MARS (YRB) 10 Churchill (YYQ) Env Canada tower site 11 BERMS site & BOREAS historical context & time series; Fire East Trout Lake disturbance/recovery sites (Rogers); Environment Canada tall tower 12 Fort Liard CFS forest inventory plots 13 Anchorage Extension of the Dalton Highway corridor; Wrangell-St Elias Dall sheep study area (Prugh) 14 King Salmon National Park Service SWAN transect Supplemental flight lines (the dashed lines in Fig. 2) offer the potential to expand the Foundational Measurements into the Canadian High Arctic and the Extended Study Region. The Foundational Measurement flight lines traverse important latitudinal and longitudinal gradients that control patterns of both precipitation and temperature. Additionally, data collected along these flight lines will sample across significant Page 8 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM variations in both topography and soil characteristics that are controlled by a range of geomorphological processes, including the impacts of glaciation and variations in surface deposition (e.g., alluvial, colluvial, and eolian processes). The variations in climate, topography, and surface geomorphology control interact to control important variations in permafrost type and ice content (see, for example, Figs A8 and A9 in the ACEP). The variations in topography, geomorphology and permafrost interact to control important gradients in surface hydrology, including soil moisture and surface water inundation. This results in a complex mosaic of terrestrial and freshwater ecosystems controlled by variations in surface hydrology, in particular landscapes where upland vegetation (forests, shrublands, and tundra) are interspersed with wetlands, peatlands, small ponds, and lakes. Furthermore, the Foundational Measurement flight lines will yield airborne remote sensing data over gradients that are caused by disturbances, providing the opportunity to understand how these disturbances affect vegetation, permafrost and surface hydrology (soil moisture and inundation). 3.1 The Alaskan Circuit The Alaskan circuit covers ~3250 km (1750 nautical miles) may be flown in a single flight day given the endurance, range and speed of the Foundational Measurement aircraft. It consists of two north-south and two east-west transects. It samples the Alaska Boreal Interior (3.1), Alaska Tundra (2.2), Brooks Range Tundra (2.3) and Boreal Cordilerra (6.1) Level II ecoregions. A more detailed description of the Alaskan circuit and intermediate points is given in Table 2. Table 2. Alaskan Circuit Flight Line Details Start End Dist (km) Dist (nm) Fairbanks (PAFA) Bethel (PABE) 850 459.0 Bethel (PABE) Emmonak 275 148.5 Emmonak Nome 200 108.0 Nome Ivotuk 620 334.8 Ivotuk Atqasuk 230 124.2 Atqasuk Barrow 100 54.0 Barrow Lake 150 81.0 Lake Deadhorse 210 113.4 Teshekpuk Deadhorse Toolik Lake 185 99.9 Teshekpuk Toolik Lake Fairbanks (PAFA) 430 232.2 TOTAL 3250 1754.9 Page 9 of 63 ABoVE Integrated Airborne Science Research Strategy 5/27/16 10:55 AM The Fairbanks – Bethel segment covers areas of high interest to USFS for the Alaska boreal forest inventory and that have been densely sampled by high spatial resolution (< 1 m) lidar and hyperspectral imagery, as well as • Eddy covariance flux towers (Ueyama) and remote sensing instrumentation at University of Alaska Fairbanks • The Bonanza Creek LTER site (BNZ, http://www.lter.uaf.edu/) including seasonal eddy covariance flux towers (Euskirchen) • a wide variety of fire recovery chronosequences including multiple burn areas > 1Mha from the 2015 fire season (ABoVE field sites) • the Whitefish Lake fire burn area (near Aniak) The Bethel – Emmonak – Nome segment spans the boreal Interior - Yukon- Kuskokwim Delta treeline and Bering Taiga as well as the unique Bering Tundra of the Seward Peninsula, including • field study sites in the YK Delta near Emmonak (Frost) • permafrost degradation sites (Schaefer) • NGEE-Arctic Seward Peninsula sites and eddy covariance flux towers at Teller, Kougarok, and council Council The Nome – Ivotuk – Atqasuk - Barrow segment links the Bering Tundra of the Seward Peninsula with a south-north transect across the western North Slope in a space for time trade: it is thought that in 50-100 years the western North Slope may resemble current conditions on the Seward Peninsula. Key field sites along this segment include • The eddy covariance flux towers at Ivotuk, Atqasuk and Barrow delivering year round CO and CH fluxes (Oechel) 2 4 • NGEE-Arctic Barrow sites with extensive characterization of land surface and sub-surface properties at < 1 m resolution • NOAA Barrow Baseline Observatory and tall tower measurements • Circumpolar Active Layer Measurement (CALM) active layer thickness sites • DOE/ARM North Slope Alaska site The North Slope provides numerous opportunities for more detailed airborne studies. For example, the Bureau of Land Management AIM intensive field sites for inventory and monitoring have been established across the North Slope (Fig. 3). Many of these plots will be sampled by the Ivotuk – Barrow – Deadhorse legs. The Barrow – Lake Teshekpuk – Deadhorse segment samples the Arctic Coastal Plain and some of the highest soil organic carbon content areas in the Arctic as well as the DOE Oliktok Point tower Page 10 of 63