Scientific Results

This catalogue is obtained by conducting a systematic literature review of scientific studies and reviews related to monitoring, forecasting, and simulating the inland water cycle. The analysis maps scientific expertise across research groups and classifies findings by the type of inland water studied, application focus, and geographical scope. A gap analysis will identify missing research areas and assess their relevance to policymaking.

ID â–Č Type Year Authors Title Venue/Journal DOI Research type Water System Technical Focus Abstract Link with Projects Link with Tools Related policies ID
publications-1451 PEER REVIEWED ARTICLE Fiehn, A., Birgit Quack, Helmke Hepach, Steffen FuhlbrĂŒgge, Susann Tegtmeier, Matthew Toohey, Elliot Atlas, and Kirstin KrĂŒger Delivery of halogenated very short-lived substances from the west Indian Ocean to the stratosphere during the Asian summer monsoon Data Management & Analytics Precipitation & Ecological Systems No abstract available 603557
publications-1452 PEER REVIEWED ARTICLE 2018 Fiehn, A., Quack, B., Stemmler, I., Ziska, F., and KrĂŒger Importance of seasonally resolved oceanic emissions for bromoform delivery from the tropical Indian Ocean and west Pacific to the stratosphere 10.5194/acp-18-11973-2018 Data Management & Analytics Precipitation & Ecological Systems Abstract. Oceanic very short-lived substances (VSLSs), such as bromoform (CHBr3), contribute to stratospheric halogen loading and, thus, to ozone depletion. However, the amount, timing, and region of bromine delivery to the stratosphere through one of the main entrance gates, the Indian summer monsoon circulation, are still uncertain. In this study, we created two bromoform emission inventories with monthly resolution for the tropical Indian Ocean and west Pacific based on new in situ bromoform measurements and novel ocean biogeochemistry modeling. The mass transport and atmospheric mixing ratios of bromoform were modeled for the year 2014 with the particle dispersion model FLEXPART driven by ERA-Interim reanalysis. We compare results between two emission scenarios: (1) monthly averaged and (2) annually averaged emissions. Both simulations reproduce the atmospheric distribution of bromoform from ship- and aircraft-based observations in the boundary layer and upper troposphere above the Indian Ocean reasonably well. Using monthly resolved emissions, the main oceanic source regions for the stratosphere include the Arabian Sea and Bay of Bengal in boreal summer and the tropical west Pacific Ocean in boreal winter. The main stratospheric injection in boreal summer occurs over the southern tip of India associated with the high local oceanic sources and strong convection of the summer monsoon. In boreal winter more bromoform is entrained over the west Pacific than over the Indian Ocean. The annually averaged stratospheric injection of bromoform is in the same range whether using monthly averaged or annually averaged emissions in our Lagrangian calculations. However, monthly averaged emissions result in the highest mixing ratios within the Asian monsoon anticyclone in boreal summer and above the central Indian Ocean in boreal winter, while annually averaged emissions display a maximum above the west Indian Ocean in boreal spring. In the Asian summer monsoon anticyclone bromoform atmospheric mixing ratios vary by up to 50 % between using monthly averaged and annually averaged oceanic emissions. Our results underline that the seasonal and regional stratospheric bromine injection from the tropical Indian Ocean and west Pacific critically depend on the seasonality and spatial distribution of the VSLS emissions. 603557
publications-1453 PEER REVIEWED ARTICLE 2017 Guermazi, Henda, Pasquale Sellitto, Mohamed Moncef Serbaji, Bernard Legras, and Farhat Rekhiss Assessment of the combined sensitivity of nadir TIR satellite observations to volcanic SO2 and sulphate aerosols after a moderate stratospheric eruption 10.3390/geosciences7030084 IoT & Sensors Precipitation & Ecological Systems Monitoring gaseous and particulate volcanic emissions with remote observations is of particular importance for climate studies, air quality and natural risk assessment. The concurrent impact of the simultaneous presence of sulphur dioxide (SO2) emissions and the subsequently formed secondary sulphate aerosols (SSA) on the thermal infraRed (TIR) satellite observations is not yet well quantified. In this paper, we present the first assessment of the combined sensitivity of pseudo-observations from three TIR satellite instruments (the Infrared Atmospheric Sounding Interferometer (IASI), the MODerate resolution Imaging Spectro radiometer (MODIS) and the Spinning Enhanced Visible and InfraRed Imager (SEVIRI)) to these two volcanic effluents, following an idealized moderate stratospheric eruption. Direct radiative transfer calculations have been performed using the 4A (Automatized Atmospheric Absorption Atlas) radiative transfer model during short-term atmospheric sulphur cycle evolution. The results show that the mutual effect of the volcanic SO2 and SSA on the TIR outgoing radiation is obvious after three to five days from the eruption. Therefore, retrieval efforts of SO2 concentration should consider the progressively formed SSA and vice-versa. This result is also confirmed by estimating the information content of the TIR pseudo-observations to the bi-dimensional retrieved vector formed by the total masses of sulphur dioxide and sulphate aerosols. We find that it is important to be careful when attempting to quantify SO2 burdens in aged volcanic plumes using broad-band instruments like SEVIRI and MODIS as these retrievals present high uncertainties. For IASI, the total errors are smaller and the two parameters can be retrieved as independent quantities. 603557
publications-1454 PEER REVIEWED ARTICLE 2018 GĂŒnther, A., Höpfner, M., Sinnhuber, B.-M., Griessbach, S., Deshler, T., von Clarmann, T., and Stiller, G MIPAS observations of volcanic sulfate aerosol and sulfur dioxide in the stratosphere 10.5194/acp-18-1217-2018 Data Management & Analytics Precipitation & Ecological Systems Abstract. Volcanic eruptions can increase the stratospheric sulfur loading by orders of magnitude above the background level and are the most important source of variability in stratospheric sulfur. We present a set of vertical profiles of sulfate aerosol volume densities and derived liquid-phase H2SO4 (sulfuric acid) mole fractions for 2005–2012, retrieved from infrared limb emission measurements performed with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board of the Environmental Satellite (Envisat). Relative to balloon-borne in situ measurements of aerosol at Laramie, Wyoming, the MIPAS aerosol data have a positive bias that has been corrected, based on the observed differences to the in situ data. We investigate the production of stratospheric sulfate aerosol from volcanically emitted SO2 for two case studies: the eruptions of Kasatochi in 2008 and Sarychev in 2009, which both occurred in the Northern Hemisphere midlatitudes during boreal summer. With the help of chemical transport model (CTM) simulations for the two volcanic eruptions we show that the MIPAS sulfate aerosol and SO2 data are qualitatively and quantitatively consistent with each other. Further, we demonstrate that the lifetime of SO2 is explained well by its oxidation by hydroxyl radicals (OH). While the sedimentation of sulfate aerosol plays a role, we find that the long-term decay of stratospheric sulfur after these volcanic eruptions in midlatitudes is mainly controlled by transport via the Brewer–Dobson circulation. Sulfur emitted by the two midlatitude volcanoes resides mostly north of 30∘ N at altitudes of ∌ 10–16 km, while at higher altitudes (∌ 18–22 km) part of the volcanic sulfur is transported towards the Equator where it is lifted into the stratospheric “overworld” and can further be transported into both hemispheres. 603557
publications-1455 PEER REVIEWED ARTICLE 2017 Hardiman, S. C., Butchart, N., O’Connor, F., Rumbold, S. T. HadGEM3-ES ChemistryClimate Model: Evaluation of stratospheric dynamics and its impact on ozone 10.5194/gmd-10-1209-2017 Data Management & Analytics Precipitation & Ecological Systems Abstract. Free-running and nudged versions of a Met Office chemistry–climate model are evaluated and used to investigate the impact of dynamics versus transport and chemistry within the model on the simulated evolution of stratospheric ozone. Metrics of the dynamical processes relevant for simulating stratospheric ozone are calculated, and the free-running model is found to outperform the previous model version in 10 of the 14 metrics. In particular, large biases in stratospheric transport and tropical tropopause temperature, which existed in the previous model version, are substantially reduced, making the current model more suitable for the simulation of stratospheric ozone. The spatial structure of the ozone hole, the area of polar stratospheric clouds, and the increased ozone concentrations in the Northern Hemisphere winter stratosphere following sudden stratospheric warmings, were all found to be sensitive to the accuracy of the dynamics and were better simulated in the nudged model than in the free-running model. Whilst nudging can, in general, provide a useful tool for removing the influence of dynamical biases from the evolution of chemical fields, this study shows that issues can remain in the climatology of nudged models. Significant biases in stratospheric vertical velocities, age of air, water vapour, and total column ozone still exist in the Met Office nudged model. Further, these can lead to biases in the downward flux of ozone into the troposphere. 603557
publications-1456 PEER REVIEWED ARTICLE 2016 Hoareau, C., V. Noel, H. Chepfer, J. Vidot, M. Chiriaco, S. Bastin, M. Reverdy, and G. Cesana Remote sensing ice supersaturation inside and near cirrus clouds: a case study in the subtropics 10.1002/asl.714 Data Management & Analytics Precipitation & Ecological Systems AbstractCombining vertically resolved lidar retrievals of water vapor and cloud detection, we document a 2‐day subtropical cirrus case study over La RĂ©union (20.9°S–55.5°E) in March 2005, focusing on the conditions of ice supersaturation inside and near the observed cloud. Using satellite observations, we describe the synoptic conditions leading to cloud formation. Supersaturation occurs 25% of the time within the cirrus, up to 35% in its middle segment, where relative humidity goes beyond 150%. In clear‐sky areas, relative humidity stays consistently low, especially in profiles without clouds. High‐troposphere atmospheric waves could initiate the formation of supersaturation conditions, especially on 16 March. 603557
publications-1457 PEER REVIEWED ARTICLE 2017 Ivy, D.J. , S. Solomon, N. Calvo, D.W.J. Thompson Observed connections of Arctic stratospheric ozone extremes to Northern Hemisphere surface climate 10.1088/1748-9326/aa57a4 Simulation & Modeling Precipitation & Ecological Systems No abstract available 603557
publications-1458 PEER REVIEWED ARTICLE 2017 Keeble, J., Bednarz, E. M., Banerjee, A., Abraham, N. L., Harris, N. R. P., Maycock, A. C., and Pyle, J. A. Diagnosing the radiative and chemical contributions to future changes in tropical column ozone with the UM-UKCA chemistry–climate model 10.5194/acp-2017-324 Simulation & Modeling Uncategorized Abstract. Chemical and dynamical drivers of trends in tropical total column ozone (TCO3) for the recent past and future periods are explored using the UM-UKCA chemistry-climate model. A transient 1960-2100 simulation is analysed which follows the representative concentration pathway 6.0 (RCP6.0) emissions scenario for the future. Tropical averaged (10° S–10° N) TCO3 values decrease from the 1970s, reaching a minimum around 2000, and return to their 1980 values around 2040, consistent with the use and emission of ozone depleting substances (ODS), and their later controls under the Montreal Protocol. However, when the ozone column is subdivided into three partial columns (PCO3) that cover the upper stratosphere (PCO3US), lower stratosphere (PCO3LS) and troposphere (PCO3T), significant differences to the behaviour of the total column are seen. Modelled PCO3T values increase from 1960–2000 before remaining steady under this particular emissions scenario throughout the 21st century. PCO3LS values decrease rapidly from 1960–2000, remain steady until around 2050, before gradually decreasing further to 2100, never recovering to their 1980s values. PCO3US values decrease from 1960–2000, before rapidly increasing throughout the 21st century, recovering to 1980s values by ~ 2020, and are significantly higher than 1980s values by 2100. Using a series of idealised UM-UKCA time-slice simulations with varying concentrations of well-mixed greenhouse gases (GHG) and ODS set to either year 2000 or 2100 levels, we examine the main processes that drive the PCO3 responses in the three regions, and assess how these processes change under different emission scenarios. Finally, we present a simple, linearised model to describe the future evolution of tropical stratospheric column ozone values based on terms representing time-dependent abundances of GHG and ODS. 603557
publications-1459 PEER REVIEWED ARTICLE 2018 Keeble, J., Brown, H., Abraham, N. L., Harris, N. R. P., and Pyle, J. A. On ozone trend detection: using coupled chemistry–climate simulations to investigate early signs of total column ozone recovery 10.5194/acp-18-7625-2018 Simulation & Modeling Precipitation & Ecological Systems Abstract. Total column ozone values from an ensemble of UM-UKCA model simulations are examined to investigate different definitions of progress on the road to ozone recovery. The impacts of modelled internal atmospheric variability are accounted for by applying a multiple linear regression model to modelled total column ozone values, and ozone trend analysis is performed on the resulting ozone residuals. Three definitions of recovery are investigated: (i) a slowed rate of decline and the date of minimum column ozone, (ii) the identification of significant positive trends and (iii) a return to historic values. A return to past thresholds is the last state to be achieved. Minimum column ozone values, averaged from 60° S to 60° N, occur between 1990 and 1995 for each ensemble member, driven in part by the solar minimum conditions during the 1990s. When natural cycles are accounted for, identification of the year of minimum ozone in the resulting ozone residuals is uncertain, with minimum values for each ensemble member occurring at different times between 1992 and 2000. As a result of this large variability, identification of the date of minimum ozone constitutes a poor measure of ozone recovery. Trends for the 2000–2017 period are positive at most latitudes and are statistically significant in the mid-latitudes in both hemispheres when natural cycles are accounted for. This significance results largely from the large sample size of the multi-member ensemble. Significant trends cannot be identified by 2017 at the highest latitudes, due to the large interannual variability in the data, nor in the tropics, due to the small trend magnitude, although it is projected that significant trends may be identified in these regions soon thereafter. While significant positive trends in total column ozone could be identified at all latitudes by ∌ 2030, column ozone values which are lower than the 1980 annual mean can occur in the mid-latitudes until ∌ 2050, and in the tropics and high latitudes deep into the second half of the 21st century. 603557
publications-1460 PEER REVIEWED ARTICLE 2017 Kleinschmitt, C., O. Boucher, S. Bekki, F. Lott, and U. Platt The Sectional Stratospheric Sulfate Aerosol module S3A-v1 within the LMDZ general circulation model: Description and evaluation against stratospheric aerosol observations 10.5194/gmd-10-3359-2017 Simulation & Modeling Precipitation & Ecological Systems Abstract. Stratospheric aerosols play an important role in the climate system by affecting the Earth's radiative budget as well as atmospheric chemistry, and the capabilities to simulate them interactively within global models are continuously improving. It is important to represent accurately both aerosol microphysical and atmospheric dynamical processes because together they affect the size distribution and the residence time of the aerosol particles in the stratosphere. The newly developed LMDZ-S3A model presented in this article uses a sectional approach for sulfate particles in the stratosphere and includes the relevant microphysical processes. It allows full interaction between aerosol radiative effects (e.g. radiative heating) and atmospheric dynamics, including e.g. an internally generated quasi-biennial oscillation (QBO) in the stratosphere. Sulfur chemistry is semi-prescribed via climatological lifetimes. LMDZ-S3A reasonably reproduces aerosol observations in periods of low (background) and high (volcanic) stratospheric sulfate loading, but tends to overestimate the number of small particles and to underestimate the number of large particles. Thus, it may serve as a tool to study the climate impacts of volcanic eruptions, as well as the deliberate anthropogenic injection of aerosols into the stratosphere, which has been proposed as a method of geoengineering to abate global warming. 603557