ALBERT

Description: NASAs Advanced Air Transport Technology (AATT) project is investigating boundary layer ingesting (BLI) propulsors for advanced subsonic commercial vehicle concepts to enable the reduction of fuel burn. A multidisciplinary team of researchers from NASA, United Technologies Research Center (UTRC), Virginia Polytechnic University, and the Air Force Arnold Engineering Development Complex developed and tested an embedded BLI inlet and distortion-tolerant fan (BLI2DTF) system in the NASA Glenn Research Center (GRC) 8- foot by 6-foot (8x6) transonic wind tunnel. The test demonstrated the component performance goals necessary for an overall fuel burn reduction of 3 to 5 percent on a large hybrid wing body (HWB) aircraft. Special test equipment, including a raised floor with flow effectors and a bleed system, was developed for use in the 8x6 to produce the appropriate incoming boundary layer representative of an HWB application. Detailed measurements were made to determine the inlet total pressure loss and distortion, fan stage efficiency, and aeromechanic performance including blade vibration stress and displacement response. Results from this test were used as input to a vehicle-level system study performed by the AATT project to assess the impact of BLI on an alternative advanced concept aircraft referred to as the NASA D8 (ND8), which is somewhat similar to the HWB in its integration of the propulsor. This paper will provide an overview of the project timeline, special test equipment needed in the wind tunnel to develop the appropriate incoming boundary layer, and the difficulties in designing a propulsor for the test. The paper will conclude with some representative aerodynamic and aeromechanic data from the test itself and conclude with how this data was used in the ND8 system study.

Description: _NASA's Advanced Air Transport Technology (AATT) project is investigating boundary layer ingesting (BLI) propulsors for advanced subsonic commercial vehicle concepts to enable the reduction of fuel burn. A multidisciplinary team of researchers from NASA, United Technologies Research Center (UTRC), Virginia Polytechnic University, and the Air Force Arnold Engineering Development Complex developed and tested an embedded BLI inlet and distortion-tolerant fan (BLI2DTF) system in the NASA Glenn Research Center (GRC) 8-foot by 6-foot (8x6) transonic wind tunnel. The test demonstrated the component performance goals necessary for an overall fuel burn reduction of 3 to 5 percent on a large hybrid wing body (HWB) aircraft. Special test equipment, including a raised floor with flow effectors and a bleed system, was developed for use in the 8x6 to produce the appropriate incoming boundary layer representative of an HWB application. Detailed measurements were made to determine the inlet total pressure loss and distortion, fan stage efficiency, and aeromechanic performance including blade vibration stress and displacement response. Results from this test were used as input to a vehicle-level system study performed by the AATT project to assess the impact of BLI on an alternative advanced concept aircraft referred to as the NASA D8 (ND8), which is somewhat similar to the HWB in its integration of the propulsor. This paper will provide an overview of the project timeline, special test equipment needed in the wind tunnel to develop the appropriate incoming boundary layer, and the difficulties in designing a propulsor for the test. The paper will conclude with some representative aerodynamic and aeromechanic data from the test itself and conclude with how this data was used in the ND8 system study.

Description: Movies: for all mapped movies (movie S1 - S6): white circles indicate the presence of a pollen record; blue dots indicate archaeological remains of wild terrestrial ungulates; and red dots indicate the remains of domestic animals. The distribution of the faunal remains was based on summed probability distributions of radiocarbon dates at 100-year time intervals (see Phelps et al. in press for further methodological information). Movie S1a: The climatic envelope of forest mapped at 100-year intervals, using the direct methodology with WorldClim data (black background). Movie S1b: The climatic envelope of forest mapped at 100-year intervals, using the direct methodology with WorldClim data (white background). Movie S1c: The climatic envelope of forest mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (black background). Movie S1d: The climatic envelope of forest taxa mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (white background). Movie S1e: The climatic envelope of forest taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (black background). Movie S1f: The climatic envelope of forest taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (white background). Movie S1g: The climatic envelope of forest taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (black background). Movie S1h: The climatic envelope of forest taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (white background). ______________________________________________________________________________________ Movie S2a: The climatic envelope of grassy biomes (savanna- and steppe-associated taxa) mapped at 100-year intervals, using the direct methodology with WorldClim data (black background). Movie S2b: The climatic envelope of grassy biomes (savanna- and steppe-associated taxa) mapped at 100-year intervals, using the direct methodology with WorldClim data (white background). Movie S2c: The climatic envelope of grassy biomes (savanna- and steppe-associated taxa) mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (black background). Movie S2d: The climatic envelope of grassy biomes (savanna- and steppe-associated taxa) mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (white background). ______________________________________________________________________________________ Movie S3a: The climatic envelope of savanna-associated taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (black background). Movie S3b: The climatic envelope of savanna-associated taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (white background). Movie S3c: The climatic envelope of savanna-associated taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (black background). Movie S3d: The climatic envelope of savanna-associated taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (white background). ______________________________________________________________________________________ Movie S4a: The climatic envelope of steppe-associated taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (black background). Movie S4b: The climatic envelope of steppe-associated taxa mapped mapped at 100-year intervals, using the indirect methodology, WorldClim data (white background). Movie S4c: The climatic envelope of steppe-associated taxa mapped mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (black background). Movie S4d: The climatic envelope of steppe-associated taxa mapped mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (white background). ______________________________________________________________________________________ Movie S5a: The climatic envelope of desert-associated taxa mapped mapped at 100-year intervals, using the direct methodology with WorldClim data (black background). Movie S5b: The climatic envelope of desert-associated taxa mapped at 100-year intervals, using the direct methodology with WorldClim data (white background). Movie S5c: The climatic envelope of desert-associated taxa mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (black background). Movie S5d: The climatic envelope of desert-associated taxa mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (white background). Movie S5e: The climatic envelope of desert-associated taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (black background). Movie S5f: The climatic envelope of desert-associated taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (white background). Movie S5g: The climatic envelope of desert-associated taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (black background). Movie S5h: The climatic envelope of desert-associated taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (white background). ______________________________________________________________________________________ Movie S6a: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the direct methodology with WorldClim data (black background). Movie S6b: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the direct methodology with WorldClim data (white background). Movie S6c: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (black background). Movie S6d: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the direct methodology with TraCE-21ka climate information (white background). Movie S6e: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (black background). Movie S6f: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the indirect methodology, WorldClim data (white background). Movie S6g: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (black background). Movie S6h: The climatic envelope of xeric-associated taxa mapped at 100-year intervals, using the indirect methodology, TraCE-21ka climate information (white background). ______________________________________________________________________________________ Movie S7a: Multivariate environmental similarity surface (MESS) analyses plotted in geographic space using the direct methodology with repeated, modern-day WorldClim data. White areas demonstrate neutrality: i.e., neither similarity nor dissimilarity. Movie S7b: Multivariate environmental similarity surface (MESS) analyses plotted in geographic space using the direct methodology with TraCE-21ka climate information. White areas demonstrate neutrality: i.e., neither similarity nor dissimilarity. Movie S7c: Multivariate environmental similarity surface (MESS) analyses plotted in geographic space using the indirect methodology with repeated, modern-day WorldClim data. White areas demonstrate neutrality: i.e., neither similarity nor dissimilarity. Movie S7d: Multivariate environmental similarity surface (MESS) analyses plotted in geographic space using the indirect methodology with TraCE-21ka climate information. White areas demonstrate neutrality: i.e., neither similarity nor dissimilarity. ______________________________________________________________________________________ Movie S8a: Climatic envelope overlap between forest and grassy biomes (savanna and steppe) plotted in climate space. Envelopes were generated using the direct methodology and TraCE-21ka climate information. Red areas indicate the presence of grassy biomes only, whereas purple indicates overlap between grassy biomes and forest. For reference to the climatic variables used to define the climate space, see the TraCE-21ka correlation circle in figure A2. Movie S8b: Climatic envelope overlap between forest and savanna only, plotted in climate space. Envelopes were generated using the indirect methodology and TraCE-21ka climate information. Red areas indicate the presence of savanna only, whereas purple indicates overlap between savanna and forest. For reference to the climatic variables used, see the TraCE-21ka correlation circle in figure A2.

Description: The Atlantic meridional overturning circulation (AMOC) is a system of ocean currents that has an essential role in Earth's climate, redistributing heat and influencing the carbon cycle. The AMOC has been shown to be weakening in recent years1; this decline may reflect decadal-scale variability in convection in the Labrador Sea, but short observational datasets preclude a longer-term perspective on the modern state and variability of Labrador Sea convection and the AMOC. Here we provide several lines of palaeo-oceanographic evidence that Labrador Sea deep convection and the AMOC have been anomalously weak over the past 150 years or so (since the end of the Little Ice Age, LIA, approximately AD 1850) compared with the preceding 1,500 years. Our palaeoclimate reconstructions indicate that the transition occurred either as a predominantly abrupt shift towards the end of the LIA, or as a more gradual, continued decline over the past 150 years; this ambiguity probably arises from non-AMOC influences on the various proxies or from the different sensitivities of these proxies to individual components of the AMOC. We suggest that enhanced freshwater fluxes from the Arctic and Nordic seas towards the end of the LIA—sourced from melting glaciers and thickened sea ice that developed earlier in the LIA—weakened Labrador Sea convection and the AMOC. The lack of a subsequent recovery may have resulted from hysteresis or from twentieth-century melting of the Greenland Ice Sheet. Our results suggest that recent decadal variability in Labrador Sea convection and the AMOC has occurred during an atypical, weak background state. Future work should aim to constrain the roles of internal climate variability and early anthropogenic forcing in the AMOC weakening described here. The data presented here is the supporting data for Thornalley et al. 2018 (see details below) and is derived from cores KNR-178-56JPC and KNR-178-48JPC. It includes the mean sortable silt size, details of radiocarbon dating, the % nps and binned sub-surface temperature reconstructions.