Description: Vulnerability to climate change and adaptation strategies of local communities in Malawi: experiences of women fish-processing groups in the Lake Chilwa Basin Hanne Jørstad and Christian Webersik Earth Syst. Dynam., 7, 977-989, doi:10.5194/esd-7-977-2016, 2016 This research is about climate change adaptation. It demonstrates how adaptation to climate change can avoid social tensions if done in a sustainable way. Evidence is drawn from Malawi in southern Africa.

Description: A wind proxy based on migrating dunes at the Baltic Coast: statistical analysis of the link between wind conditions and sand movement Svenja E. Bierstedt, Birgit Hünicke, Eduardo Zorita, and Juliane Ludwig Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-71,2016 Manuscript under review for ESD (discussion: open, 0 comments) We statistically analyse the relationship between the structure of migrating dunes in the Southern Baltic and the driving wind conditions over the past 26 years, with the long-term aim of using migrating dunes as proxy for past wind conditions at interannual resolution. Dunes as wind proxies are not a totally new idea to the scientific community, but existing studies have so far analysed the link of dune structure and wind only on temporal resolutions of decades or millennia. The present analysis is based on the dune record derived from geo-radar measurements by Ludwig et al. (2016). The dune system is located at the Baltic Sea coast of Poland and is migrating from west to east along the coast. Ludwig et al. (2016) suggested that the analysed dunes show an alternation in the sediment composition that can be used to determine the annual migration velocity which can be seen as a wind proxy. Here, we present a detailed statistical analysis of this record and calibrate it as a wind proxy. To our knowledge there are no adequate, homogeneous meteorological station data for this area available to validate this proxy. Therefore we based our analysis on a gridded regional meteorological reanalysis data set (coastDat2) over the recent decades. We include precipitation and temperature into our analysis, in addition to wind, to learn more about the dependency between these three atmospheric factors and their common influence on the dune system. We set up a statistical linear model based on the correlation between the number of days with west and south-west wind directions above a pre-defined wind speed threshold and the dune migration velocities. To some extent, the dune intervals can be seen analogous to a tree ring widths, and hence we used a proxy-validation method usually applied in dendrochronology when the available meteorological record is short, namely the cross-validation with the leave-one-out-method. This revealed correlations between the wind record from the reanalysis and the reconstructed wind record derived from the dune structure in the range of 0.28 and 0.63. Thus, our study verifies that this type of dunes can be validated with dendrochronological methods and derive acceptable validation values as a wind proxy. The identified link between the dune annual layers and wind conditions from the meteorological reanalysis was additionally supported by the co-variability between dune layers and sea-level variations in the Southern Baltic Sea. Baltic Sea level variability in winter time is known to be strongly driven by westerly winds over this region. These results, therefore, provide an independent support, solely based on observations, of the link between annual dune layers and prevailing wind conditions.

Description: Satellite altimetry reveals spatial patterns of variations in the Baltic Sea wave climate Nadezhda Kudryavtseva and Tarmo Soomere Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-68,2016 Manuscript under review for ESD (discussion: open, 0 comments) We discuss for the first time changes in the wave climate in the Baltic Sea over the last two decades derived from the satellite altimetry data spanning over 26 years. We found in the study that there are variations in the wave climate of the Baltic Sea, which can be interpreted as being caused predominantly by a rotation of wind directions rather than increased wind speed, implying that associated variations in the airflow direction can be a dominant driver of regional climate changes.

Description: Sensitivity Experiments on the Response of Vb Cyclones to Ocean Temperature and Soil Moisture Changes Martina Messmer, Juan José Gómez-Navarro, and Christoph C. Raible Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-67,2016 Manuscript under review for ESD (discussion: open, 0 comments) Extra-tropical cyclones of type Vb, which develop over the western Mediterranean and move northeastward, are major natural hazards being responsible for heavy precipitation over Central Europe. To gain further understanding in the governing processes of these Vb cyclones the stu-dy explores the role of soil moisture and sea surface temperature (SST) and their contribution to the atmospheric moisture content. Thereby, recent Vb events identified in the ERA-Interim reanalysis are dynamically downscaled with the Weather Research and Forecasting model (WRF). Results indicate that a mean Vb event is mostly sensitive to an increase in the Mediterranean SSTs, e.g., an increase of +5 K leads to an average increase of 24 % in precipitation over Central Europe. This increase in precipitation is mainly induced by larger mean upward moisture flux over the Mediterranean with increasing Mediterranean SSTs. This further invokes an increase in latent energy release, which leads to an increase in atmospheric instability, i.e., in convective available potential energy. Both, the increased availability of atmospheric moisture and the increased instability of the atmosphere, which is able to remove extra moisture from the atmosphere due to convective processes, are responsible for the strong increase in precipitation over the entire region influenced by Vb events. Precipitation patterns further indicate that a strong increase in precipitation is found at the eastern coast of the Adriatic Sea for increased Mediterranean SSTs. This premature loss in atmospheric moisture leads to a significant decrease in atmospheric moisture transport to Central Europe and the northeastern flanks of the Alpine mountain chain. This leads to a reduction in precipitation in this high-impact region of the Vb event for an increase in Mediterranean SSTs of +5 K. Furthermore, the intensity of the Vb cyclones, measured as a gradient in the 850-hPa geopotential height field around the cyclone centre, indicates that an upper bound for intensity might be reached for the most intense Vb event. This fact indicates that strong cyclones are more strongly steered by the present atmospheric conditions.

Description: Weather and resource information as tools for dealing with farmer–pastoralist conflicts in the Sahel Ole Mertz, Kjeld Rasmussen, and Laura Vang Rasmussen Earth Syst. Dynam., 7, 969-976, doi:10.5194/esd-7-969-2016, 2016 Conflicts over land and water resources between livestock herders and farmers are common in the Sahelian region of Africa. In this paper we show that improved information on weather, grazing areas, and water resources may reduce the level of conflict if communicated in such a way so that not too many livestock herds go to the same areas. However, if this information is not accompanied by information on herd crowding and potential conflict areas, it may lead to more conflict.

Description: Presence of continental and Bay of Bengal moisture in rainfall at Kolkata, revealed through simultaneous observation from land and sea during South-West monsoon of 2004 Shaakir Shabir Dar and Prosenjit Ghosh Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-63,2016 Manuscript under review for ESD (discussion: open, 0 comments) The backward air mass trajectory analysis (HYSPLIT) during the summer monsoon suggests that the rain which precipitates at Kolkata is generated from a moisture parcel which originates from the Arabian Sea and moves inland over the dry Indian subcontinent or over the Bay of Bengal. We used monthly satellite and ground based measurements of the hydro-meteorological variables together with isotope data from Bangalore, Bay of Bengal and Kolkata and other locations to quantify the contribution of different moisture sources during the SW Monsoon. The vapor mass as it moves under the prevailing wind direction was subjected to isotopic modification due to addition of evaporated moisture from Bay of Bengal and rainout process. This was simulated using Craig and Gordon model and Rayleigh fractionation model respectively. The moisture generated during the process of evaporation from Bay of Bengal surface ocean gets advected towards the continent and precipitates as rainfall or snowfall over the Indo-Gangetic plain. We assumed based on our observation that the initial isotopic composition of vapor originating from the peninsular continental source is similar to our observation recorded at Bangalore station. It is found that the isotopic signature of Bangalore is completely lost albeit the significant contribution of the moisture from Bay of Bengal. To explain the isotopic composition of precipitation at Kolkata during the SW-Monsoon, it was necessary to invoke 75–80 % moisture contribution from the Bay of Bengal whereas the evaporated moisture parcel from the Peninsular India contribute 25 %–35 %.

Description: Deforestation in Amazonia impacts riverine carbon dynamics Fanny Langerwisch, Ariane Walz, Anja Rammig, Britta Tietjen, Kirsten Thonicke, and Wolfgang Cramer Earth Syst. Dynam., 7, 953-968, doi:10.5194/esd-7-953-2016, 2016 Amazonia is heavily impacted by climate change and deforestation. During annual flooding terrigenous material is imported to the river, converted and finally exported to the ocean or the atmosphere. Changes in the vegetation alter therefore riverine carbon dynamics. Our results show that due to deforestation organic carbon amount will strongly decrease both in the river and exported to the ocean, while inorganic carbon amounts will increase, in the river as well as exported to the atmosphere.

Description: Assessment of the nuclear power plant "Hanhikivi-1" influence on the local hydrological conditions in the Bothnian Bay, Baltic Sea Anton Dvornikov, Stanislav Martyanov, Vladimir Ryabchenko, Tatjana Eremina, Alexey Isaev, and Dmitry Sein Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-69,2016 Manuscript under review for ESD (discussion: open, 0 comments) The results of the study aimed to assess the influence of future nuclear power plant "Hanhikivi-1" upon the local hydrological conditions in the Bothnian Bay in the Baltic Sea are presented. A number of experiments with different numerical models were also carried out in order to estimate the extreme hydro-meteorological conditions in the area of the construction. The numerical experiments were fulfilled both with analytically-specified external forcing and with real external forcing for two years: a cold year (2010) and a warm year (2014). The study has shown that the extreme values of sea level, water temperature, the characteristics of wind waves and sea ice in the vicinity of the future nuclear power plant can be significant and sometimes catastrophic. Permanent release of heat into the marine environment from operating nuclear power plant will lead to a strong increase in temperature and the disappearance of ice cover around 2 km vicinity of the station. These effects should be taken into account when assessing local climate changes in the future.

Description: Role of moisture transport for Central American precipitation Ana María Durán-Quesada, Luis Gimeno, and Jorge Amador Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-66,2016 Manuscript under review for ESD (discussion: open, 0 comments) This work aims to leverage the understanding of precipitation distribution with a long term analysis of moisture transport from oceanic and continental sources and its relevance for regional precipitation features, variability and trends. Combining reanalysis, model output, in situ observations and satellite products we provide a robust survey, useful for modeling, water resources management, flood and drought monitoring, rain-linked diseases spread and ecosystem studies among others.

Description: Drought and Flood in the Anthropocene: Modelling Feedback Mechanisms Giuliano Di Baldassarre, Fabian Martinez, Zahra Kalantari, and Alberto Viglione Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-65,2016 Manuscript under review for ESD (discussion: open, 0 comments) There is still little understanding about human-water interactions and, as a result, policies and measures to reduce hydrological risk (floods or droughts) can lead to unintended consequences. This paper proposes a research agenda to improve our understanding of human-water interactions, and presents an initial attempt to model the reciprocal effects between water management, droughts and floods.