Evapotranspiration Estimation with the S-SEBI Method from Landsat 8 Data against Lysimeter Measurements at the Barrax Site, Spain

Evapotranspiration (ET) is a variable of the climatic system and hydrological cycle that plays an important role in biosphere–atmosphere–hydrosphere interactions. In this paper, remote sensing-based ET estimates with the simplified surface energy balance index (S-SEBI) model using Landsat 8 data were compared with in situ lysimeter measurements for different land covers (Grass, Wheat, Barley, and Vineyard) at the Barrax site, Spain, for the period 2014–2018. Daily estimates produced superior performance than hourly estimates in all the land covers, with an average difference of 12% and 15% for daily and hourly ET estimates, respectively. Grass and Vineyard showed the best performance, with an RMSE of 0.10 mm/h and 0.09 mm/h and 1.11 mm/day and 0.63 mm/day, respectively. Thus, the S-SEBI model is able to retrieve ET from Landsat 8 data with an average RMSE for daily ET of 0.86 mm/day. Some model uncertainties were also analyzed, and we concluded that the overpass of the Landsat missions represents neither the maximum daily ET nor the average daily ET, which contributes to an increase in errors in the estimated ET. However, the S-SEBI model can be used to operationally retrieve ET from agriculture sites with good accuracy and sufficient variation between pixels, thus being a suitable option to be adopted into operational ET remote sensing programs for irrigation scheduling or other purposes.

Upper pliocene diatom complexes and its significfnce to establish lower boundary of quarter (South of the Far East)

An analysis of the evolutionary distribution of diatoms in the outcrops of the Late Cenozoic shows that, upon reaching the level of the Annensky Horizon (Gelazian stage), the extinct species disappear almost completely. A predominance of the alluvial type of sedimentogenesis and reduction in the lake basins areas are clearly registered for deposits of the diatom zone Aulacoseira praegranulata var. praeislandica f. praeislandica. A cooling in the Late Pliocene with the pronounced temperature minimum at the level about 2,58 million years is fairly bright reflected in the ecological structures of diatomic associations (upper complex): the benthic arcto- and north-boreal flora predominates. Of that time, a total absence of the pollen of the broad-leaved species is also characteristic and paleo-landscapes become close to the Eopleistocene ones. From this moment on, the coexistence and expansion of the polar ice sheets begin (transition of planet from the “Green house” mode to the “Ice house” mode) which determine the formation of the modern climatic system of the Earth which emphasizes the globality of the palaeoclimatic event. From the lithological point of view, the bottom of the red rocks strata of the Annensky Horizon corresponding to the Gelazian stage bottom (2,58 million years) coincides with this boundary in the southern Primorye. The age changes of the Quarter boundary to this chronostratigrahic level is well founded.

Quantification of the Direct Solar Impact on Some Components of the Hydro-Climatic System

This study addresses the causal links between external factors and the main hydro-climatic variables by using a chain of methods to unravel the complexity of the direct sun–climate link. There is a gap in the literature on the description of a complete chain in addressing the structures of direct causal links of solar activity on terrestrial variables. This is why the present study uses the extensive facilities of the application of information theory in view of recent advances in different fields. Additionally, by other methods (e.g., neural networks) we first tested the existent non-linear links of solar–terrestrial influences on the hydro-climate system. The results related to the solar impact on terrestrial phenomena are promising, which is discriminant in the space-time domain. The implications prove robust for determining the causal measure of climate variables under direct solar impact, which makes it easier to consider solar activity in climate models by appropriate parametrizations. This study found that hydro-climatic variables are sensitive to solar impact only for certain frequencies (periods) and have a coherence with the Solar Flux only for some lags of the Solar Flux (in advance).

Self-adaptive multi-objective climate policies align mitigation and adaptation strategies

With intensifying climate change impacts, there is a risk that economic resources needed to adapt to the rising damages are diverted away from emission reduction, jeopardizing the chances of stabilizing temperature within safe levels. Indeed, the traditional static single-objective formulation leads to a conflict between mitigation and adaptation, invalidating the recently established consistency of cost-benefit analysis with Paris agreement targets. Here, we show that this tension can be resolved by integrating multi-objective optimization and feedback control in the DICE model to design self-adaptive climate policies trading off welfare maximization with Paris Agreement achievement. These policies allow adjusting against uncertainty as information on the socio-climatic system accumulates thus more realistically representing the policy-making process. Years above 2°C are drastically reduced, and costs of meeting the Paris agreement lowered by 2 trillion USD emphasizing the need for integrating adaptation and mitigation strategies and the value of embracing a self-adaptive and multi-objective perspective.

Half-precession signals in Lake Ohrid and their spatial and temporal connection to proxy records in the European realm

<p>Lake Ohrid is located on the Balkan Peninsula between Albania and North Macedonia. It is considered Europe’s oldest lake and thus is a valuable archive for studies that focus on the change of local (hydro-)climate during the last 1.36 million years (e.g., Francke et al. 2016; Wagner et al. 2019). During an International Continental Scientific Drilling Program (ICDP) campaign in 2013, geophysical downhole logging by the Leibniz Institute for Applied Geophysics acquired continuous datasets of physical properties. Additionally, 2100 m of sediment core was obtained from different sites, the deepest with a length of 570 m (Wagner et al. 2014).</p><p>Investigations of half-precession (HP) cycles (~9,000 – 12,000 years) have been given only a small role or have been completely neglected in previous cyclostratographic studies. In this study we focus on HP signals in Lake Ohrid and investigate the temporal variability of this signal over the last one million of years. Next to a connection of HP cycles to interglacials, we see a more pronounced correlation of the HP signal to natural gamma radiation logs in the younger part of the record.</p><p>We relate the results from Lake Ohrid to a variety of proxy records from the European mainland and marine sediment cores from the Atlantic and the Mediterranean. Certain patterns, such as the increased visibility of the HP signal in interglacials, occur in most records, but differences, like variations in the amplitude modulation of the filtered HP signal, need to be investiagted in more detail. Nevertheless, the HP cycles are contained in all of the investigated sites, although the records are influenced by different climatic systems. This illustrates that HP signals cannot be connected to a certain climatic system, but can occur simultaneously in records with different proxy signal origins.</p><p>HP cycles are a relevant part of natural climate variability - also in Europe - and allow a more detailed investiagtion of sedimentary systems.</p><p> </p><p>References:</p><p>Francke, A., Wagner, B., Just, J., Leicher, N., Gromig, R., Baumgarten, H., … & Giacco, B. (2016). Sedimentological processes and environmental variability at Lake Ohrid (Macedonia, Albania) between 637 ka and the present, Biogeosciences , 13, 1179–1196.</p><p>Wagner, B., Wilke, T., Krastel, S., Zanchetta, G., Sulpizio, R., Reicherter, K., …. & Vogel, H. (2014). The SCOPSCO drilling project recovers more than 1.2 million years of history from Lake Ohrid, Sci. Drill. , 17, 19-29.</p><p>Wagner, B., Vogel, H., Francke, A., Friedrich, T., Donders, T., Lacey, J. H., … & Zhang, X. . (2019). Mediterranean winter rainfall in phase with African monsoons during the past 1.36 million years, Nature , 573(7773), 256-260.</p>

Recent global decline of CO2 fertilization effects on vegetation photosynthesis

The enhanced vegetation productivity driven by increased concentrations of carbon dioxide (CO2) [i.e., the CO2 fertilization effect (CFE)] sustains an important negative feedback on climate warming, but the temporal dynamics of CFE remain unclear. Using multiple long-term satellite- and ground-based datasets, we showed that global CFE has declined across most terrestrial regions of the globe from 1982 to 2015, correlating well with changing nutrient concentrations and availability of soil water. Current carbon cycle models also demonstrate a declining CFE trend, albeit one substantially weaker than that from the global observations. This declining trend in the forcing of terrestrial carbon sinks by increasing amounts of atmospheric CO2 implies a weakening negative feedback on the climatic system and increased societal dependence on future strategies to mitigate climate warming.

Changes in atmospheric and hydrological dynamics at the Colombian Amazon in scenarios of forest loss

<p>The Colombian Amazon exhibits complex hydro-meteorological features, as it links the biggest tropical rainforest of the world with the Andes range and the savannahs of the Orinoco basin. Similar to other amazon areas in neighboring countries, this high-biodiversity region faces severe deforestation due the agricultural expansion, illegal logging, and mining. Numerous studies have stated the role of the Amazon over the climatic system, and the complex interactions between the rainforest, the atmospheric dynamics and the hydrological response of the rivers. Furthermore, previous studies have warned about the effects of the loss of vegetal coverage in the Amazon over hydro-meteorological patterns in northern South America.</p><p>This work aims to study the effects of deforestation over some atmospheric and hydrological features in the Colombian Amazon. Taking into account present and historical rates of deforestation, there are defined scenarios of moderate and intense forest loss. Changes in precipitation and moisture fluxes over the area are investigated using the atmospheric model WRF (Weather Research and Forecasting). High-resolution simulations are performed for a study period composed of typical rainy and dry months, considering the changes in land use of each scenario. The effects of forest loss over streamflow in some rivers of the region are assessed using the results from the atmospheric model and simulations in an aggregated hydrological model. The main finding suggests that low-level moisture flux over the Colombian Amazon and neighboring Andean foothills decrease with the reduction of the rainforest cover in both of the considered seasons. As a consequence, precipitation decreases over the area, triggering a reduction of the streamflow in the studied rivers.</p>

On the myths in hydrology and in other earth sciences

Following scientific myths, which are widely spread in hydrology and in other earth sciences, are discussed. (1) The total water mass on land surface statistically significantly diminishes during last century. (2) Many time series of annual river runoff demonstrate nonstationary character. (3) The first-order Markov chain is a dominating model in the stochastic description of the long time series of annual runoff. (4) Because of the global heating, annual discharges of the northern rivers will inevitably grow during the 21st century. (5) The main contribution to uncertainty of the forecast of the runoff through the end of the 21st century is made by uncertainty in scenarios of emission of greenhouse gases and divergences in results of modeling of the climatic system by GCMs. (6) The most shocking myth: the idea of the deterministic positive trend within the mean global temperature during last 100 years.

Anthropocenic Limitations to Climate Engineering

The development of climate engineering research has historically depended on mostly western, holistic perceptions of climate and climate change. Determinations of climate and climate change as a global system have played a defining role in the development of climate engineering. As a result, climate engineering research in general, and solar radiation management (SRM) in particular, is primarily engaged in research of quantified, whole-Earth solutions. I argue that in the potential act of solar radiation management, a view of climate change that relies on the holistic western science of the climatic system is enshrined. This view, dependent on a deliberative intentionality that seems connected to anthropocenic notions of responsibility and control, profoundly influences the assumptions and research methods connected to climate engineering. While this may not necessarily be to the detriment of climate engineering proposals—in fact, it may be the only workable conception of SRM—it is a conceptual limit to the enterprise that has to be acknowledged. Additionally, in terms of governance, reliability, and cultural acceptance, this limit could be a fundamental objection to future experimentation (or implementation).