Gulev
Sergey
Gulev
Sergey
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ArticleNorthern Eurasia Future Initiative (NEFI) : facing the challenges and pathways of global change in the twenty-first century(Springer, 2017-12-27) Groisman, Pavel Ya ; Shugart, Herman ; Kicklighter, David W. ; Henebry, Geoffrey ; Tchebakova, Nadezhda ; Maksyutov, Shamil ; Monier, Erwan ; Gutman, Garik ; Gulev, Sergey ; Qi, Jiaguo ; Prishchepov, Alexander ; Kukavskaya, Elena ; Porfiriev, Boris ; Shiklomanov, Alexander ; Loboda, Tatiana ; Shiklomanov, Nikolay ; Nghiem, Son ; Bergen, Kathleen ; Albrechtová, Jana ; Chen, Jiquan ; Shahgedanova, Maria ; Shvidenko, Anatoly ; Speranskaya, Nina ; Soja, Amber ; de Beurs, Kirsten ; Bulygina, Olga N ; McCarty, Jessica ; Zhuang, Qianlai ; Zolina, OlgaDuring the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to better prepare societies for future developments. A key principle of NEFI is that these developments must now be secured through science-based strategies co-designed with regional decision-makers to lead their societies to prosperity in the face of environmental and institutional challenges. NEESPI scientific research, data, and models have created a solid knowledge base to support the NEFI program. This paper presents the NEFI research vision consensus based on that knowledge. It provides the reader with samples of recent accomplishments in regional studies and formulates new NEFI science questions. To address these questions, nine research foci are identified and their selections are briefly justified. These foci include warming of the Arctic; changing frequency, pattern, and intensity of extreme and inclement environmental conditions; retreat of the cryosphere; changes in terrestrial water cycles; changes in the biosphere; pressures on land use; changes in infrastructure; societal actions in response to environmental change; and quantification of Northern Eurasia’s role in the global Earth system. Powerful feedbacks between the Earth and human systems in Northern Eurasia (e.g., mega-fires, droughts, depletion of the cryosphere essential for water supply, retreat of sea ice) result from past and current human activities (e.g., large-scale water withdrawals, land use, and governance change) and potentially restrict or provide new opportunities for future human activities. Therefore, we propose that integrated assessment models are needed as the final stage of global change assessment. The overarching goal of this NEFI modeling effort will enable evaluation of economic decisions in response to changing environmental conditions and justification of mitigation and adaptation efforts.
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ArticleAir-sea fluxes with a focus on heat and momentum(Frontiers Media, 2019-07-31) Cronin, Meghan F. ; Gentemann, Chelle L. ; Edson, James B. ; Ueki, Iwao ; Bourassa, Mark A. ; Brown, Shannon ; Clayson, Carol A. ; Fairall, Christopher W. ; Farrar, J. Thomas ; Gille, Sarah T. ; Gulev, Sergey ; Josey, Simon A. ; Kato, Seiji ; Katsumata, Masaki ; Kent, Elizabeth ; Krug, Marjolaine ; Minnett, Peter J. ; Parfitt, Rhys ; Pinker, Rachel T. ; Stackhouse, Paul W., Jr. ; Swart, Sebastiaan ; Tomita, Hiroyuki ; Vandemark, Douglas ; Weller, Robert A. ; Yoneyama, Kunio ; Yu, Lisan ; Zhang, DongxiaoTurbulent and radiative exchanges of heat between the ocean and atmosphere (hereafter heat fluxes), ocean surface wind stress, and state variables used to estimate them, are Essential Ocean Variables (EOVs) and Essential Climate Variables (ECVs) influencing weather and climate. This paper describes an observational strategy for producing 3-hourly, 25-km (and an aspirational goal of hourly at 10-km) heat flux and wind stress fields over the global, ice-free ocean with breakthrough 1-day random uncertainty of 15 W m–2 and a bias of less than 5 W m–2. At present this accuracy target is met only for OceanSITES reference station moorings and research vessels (RVs) that follow best practices. To meet these targets globally, in the next decade, satellite-based observations must be optimized for boundary layer measurements of air temperature, humidity, sea surface temperature, and ocean wind stress. In order to tune and validate these satellite measurements, a complementary global in situ flux array, built around an expanded OceanSITES network of time series reference station moorings, is also needed. The array would include 500–1000 measurement platforms, including autonomous surface vehicles, moored and drifting buoys, RVs, the existing OceanSITES network of 22 flux sites, and new OceanSITES expanded in 19 key regions. This array would be globally distributed, with 1–3 measurement platforms in each nominal 10° by 10° box. These improved moisture and temperature profiles and surface data, if assimilated into Numerical Weather Prediction (NWP) models, would lead to better representation of cloud formation processes, improving state variables and surface radiative and turbulent fluxes from these models. The in situ flux array provides globally distributed measurements and metrics for satellite algorithm development, product validation, and for improving satellite-based, NWP and blended flux products. In addition, some of these flux platforms will also measure direct turbulent fluxes, which can be used to improve algorithms for computation of air-sea exchange of heat and momentum in flux products and models. With these improved air-sea fluxes, the ocean’s influence on the atmosphere will be better quantified and lead to improved long-term weather forecasts, seasonal-interannual-decadal climate predictions, and regional climate projections.
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ArticleUnexpected impacts of the Tropical Pacific array on reanalysis surface meteorology and heat fluxes(John Wiley & Sons, 2014-09-03) Josey, Simon A. ; Yu, Lisan ; Gulev, Sergey ; Jin, Xiangze ; Tilinina, N. ; Barnier, B. ; Brodeau, L.The Tropical Pacific mooring array has been a key component of the climate observing system since the early 1990s. We identify a pattern of strong near surface humidity anomalies, colocated with the array, in the widely used European Center for Medium Range Weather Forecasting Interim atmospheric reanalysis. The pattern generates large, previously unrecognized latent and net air-sea heat flux anomalies, up to 50 Wm−2 in the annual mean, in reanalysis derived data sets employed for climate studies (TropFlux) and ocean model forcing (the Drakkar Forcing Set). As a consequence, uncertainty in Tropical Pacific ocean heat uptake between the 1990s and early 2000s at the mooring sites is significant with mooring colocated differences in decadally averaged ocean heat uptake as large as 20 Wm−2. Furthermore, these results have major implications for the dual use of air-sea flux buoys as reference sites and sources of assimilation data that are discussed.