Heinrich events show two-stage climate response in transient glacial simulations Climate of the Past DOI 10.5194/cp-15-153-2019 24 January 2019 Heinrich events are among the dominant modes of glacial climate variability. They are caused by massive ice discharges from the Laurentide Ice Sheet into the North Atlantic. In previous studies, the climate changes were either seen as resulting from freshwater released from the melt of the discharged icebergs or by ice sheet elevation changes. With a coupled ice sheet–climate model, we show that both effects are relevant with the freshwater effects preceding the ice sheet elevation effects. Read more
Quantifying new water fractions and transit time distributions using ensemble hydrograph separation: theory and benchmark tests Hydrology and Earth System Sciences DOI 10.5194/hess-23-303-2019 18 January 2019 How long does it take for raindrops to become streamflow? Here I propose a new approach to this old problem. I show how we can use time series of isotope data to measure the average fraction of same-day rainfall appearing in streamflow, even if this fraction varies greatly from rainstorm to rainstorm. I show that we can quantify how this fraction changes from small rainstorms to big ones, and from high flows to low flows, and how it changes with the lag time between rainfall and streamflow. Read more
Global atmospheric CO2 inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate Biogeosciences DOI 10.5194/bg-16-117-2019 16 January 2019 We have compared global carbon budgets calculated from numerical inverse models and CO2 observations, and evaluated how these systems reproduce vertical gradients in atmospheric CO2 from aircraft measurements. We found that available models have converged on near-neutral tropical total fluxes for several decades, implying consistent sinks in intact tropical forests, and that assumed fossil fuel emissions and predicted atmospheric growth rates are now the dominant axes of disagreement. Read more
A multi-technology analysis of the 2017 North Korean nuclear test Solid Earth DOI 10.5194/se-10-59-2019 15 January 2019 On 3 September 2017 official channels of the Democratic People’s Republic of Korea announced the successful test of a nuclear device. This study provides a multi-technology analysis of the 2017 North Korean event and its aftermath using a wide array of geophysical methods (seismology, infrasound, remote sensing, radionuclide monitoring, and atmospheric transport modeling). Our results clearly indicate that the September 2017 North Korean event was in fact a nuclear test. Read more
Demystifying academics to enhance university–business collaborations in environmental science Geoscience Communication DOI 10.5194/gc-2-1-2019 15 January 2019 Worldwide there is intense interest in converting research excellence in universities into commercial success, but there has been scant attention devoted to exactly how individual scientists’ workload and incentive structures may be a key barrier to this. Our work reveals the real challenge posed by a time-constrained university culture, better describes how work with business might fit into an academic job, and gives tips on working together in anuser guidefor scientists and (re)insurers. Read more
Indian winter and summer monsoon strength over the 4.2 ka BP event in foraminifer isotope records from the Indus River delta in the Arabian Sea Climate of the Past DOI 10.5194/cp-15-73-2019 15 January 2019 A foraminifer oxygen isotope record from the northeastern Arabian Sea was used to reconstruct winter and summer monsoon strength from 5.4 to 3.0 ka. We found a 200-year period of strengthened winter monsoon (4.5–4.3 ka) that coincides with the earliest phase of the Mature Harappan period of the Indus Civilization, followed by weakened winter and summer monsoons by 4.1 ka. Aridity spanning both rainfall seasons at 4.1 ka may help to explain some of the observed archaeological shifts. Read more
Volatile organic compounds and ozone in Rocky Mountain National Park during FRAPPÉ Atmospheric Chemistry and Physics DOI 10.5194/acp-19-499-2019 14 January 2019 Rocky Mountain National Park experiences high ozone concentrations that can exceed the National Ambient Air Quality Standard. As part of the FRAPPÉ field campaign, a suite of volatile organic compounds were measured to characterize the sources of ozone precursors that contribute to high ozone in the park. These measurements indicate emissions from the Front Range in Colorado tied to oil and gas operations, urban areas, and the stratosphere contribute to episodes of elevated ozone. FRAPPÉ">Read more
Atmospheric histories, growth rates and solubilities in seawater and other natural waters of the potential transient tracers HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116 Ocean Science DOI 10.5194/os-15-33-2019 11 January 2019 Use of CFCs as oceanic transient tracers is difficult for recently ventilated water masses as their atmospheric mole fractions have been decreasing. To explore novel tracers, we synthesized consistent annual mean atmospheric histories of HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 (CF4) and PFC-116 in both hemispheres and reconstructed their solubility functions in water and seawater. This work is also potentially useful for tracer studies in a range of natural waters. HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116">Read more
Structural changes in the shallow and transition branch of the Brewer–Dobson circulation induced by El Niño Atmospheric Chemistry and Physics DOI 10.5194/acp-19-425-2019 11 January 2019 This paper assesses the structural changes in the shallow and transition branches of the BDC induced by El Nino using the Lagrangian model simulations driven by ERAi and JRA-55 combined with MLS observations. We found a clear evidence of a weakening of the transition branch due to an upward shift in the dissipation height of the planetary and gravity waves and a strengthening of the shallow branch due to enhanced GW breaking in the tropics–subtropics and PW breaking at high latitudes. Read more
Refining physical aspects of soil quality and soil health when exploring the effects of soil degradation and climate change on biomass production: an Italian case study SOIL DOI 10.5194/soil-5-1-2019 10 January 2019 This study is restricted to soil physical aspects of soil quality and health with the objective to define procedures with worldwide rather than only regional applicability, reflecting modern developments in soil physical research and focusing on important questions regarding possible effects of soil degradation and climate change. Read more
