scholarly journals Added value of a Convection Permitting Model in simulating Atmospheric Water cycle over the Asian Water Tower

2021 ◽  
Author(s):  
Yin Zhao ◽  
Tianjun Zhou ◽  
Puxi Li ◽  
Kalli Furtado ◽  
Liwei Zou
Keyword(s):  
Water Cycle ◽  
Added Value ◽  
Atmospheric Water ◽  
Asian Water

scholarly journals Training hydrologists to be ecohydrologists: a "how-you-can-do-it" example leveraging an active learning environment for studying plant-water interaction

2012 ◽  
Vol 9 (8) ◽  
pp. 9337-9360
Author(s):  
S. W. Lyon ◽  
M. T. Walter ◽  
E. J. Jantze ◽  
J. A. Archibald
Keyword(s):  
Active Learning ◽  
Learning Strategies ◽  
Teaching And Learning ◽  
Water Cycle ◽  
Added Value ◽  
Plant Water ◽  
Learning Approaches ◽  
Master's Students ◽  
Cornell University ◽  
Learn By Doing

Abstract. Structuring an education strategy capable of addressing the various spheres of ecohydrology is difficult due to the inter-disciplinary and cross-disciplinary nature of this emergent field. Clearly, there is a need for such strategies to accommodate more progressive educational concepts while highlighting a skills-based education. To demonstrate a possible way to develop courses that include such concepts, we offer a case-study or a "how-you-can-do-it" example from an ecohydrology course recently co-taught by teachers from Stockholm University and Cornell University at the Navarino Environmental Observatory (NEO) in Costa Navarino, Greece. This course focused on introducing hydrology Master's students to some of the central concepts of ecohydrology while at the same time supplying process-based understanding relevant for characterizing evapotranspiration. As such, the main goal of the course was to explore central theories in ecohydrology and their connection to plant-water interactions and the water cycle in a semiarid environment. In addition to presenting this roadmap for ecohydrology course development, we explore the utility and effectiveness of adopting active teaching and learning strategies drawing from the suite of learn-by-doing, hands-on, and inquiry-based techniques in such a course. We test a gradient of "activeness" across a sequence of three teaching and learning activities. Our results indicate that there was a clear advantage for utilizing active learning techniques in place of traditional lecture-based styles. In addition, there was a preference among the student towards the more "active" techniques. This demonstrates the added value of incorporating even the simplest active learning approaches in our ecohydrology (or general) teaching.

Linking Lagrangian model simulations with stable water isotope measurements in Arctic weather systems.

2021 ◽  
Author(s):  
Aina Johannessen ◽  
Alena Dekhtyareva ◽  
Andrew Seidl ◽  
Harald Sodemann
Keyword(s):  
Water Cycle ◽  
Lagrangian Model ◽  
Water Isotopes ◽  
Stable Water Isotopes ◽  
Atmospheric Water ◽  
Model Simulations ◽  
Evaporation Source ◽  
Isotope Measurements ◽  
Water Isotope ◽  
Eulerian Models

<p>Transport of water from an evaporation source towards a precipitation sink is the essence of the atmospheric water cycle. However, there are significant challenges with the representation of the atmospheric water cycle in models. For example, incomplete representation of sub-grid scale processes like evaporation, mixing or precipitation can lead to substantial model errors. Here we investigate the combined use of Lagrangian and Eulerian models and in-situ observations of stable water isotopes to reduce such sources of model error. The atmospheric water cycle in the Nordic Seas during cold air outbreaks (CAOs) is confined to a limited area, and thus may be used as a natural laboratory for hydrometeorological studies. We apply Lagrangian and Eulerian models together with observations taken during the ISLAS2020 field campaign in the Arctic in spring 2020 for characterising source-sink relationships in the water cycle. During the field campaign, we observed an alternating sequence of cold air outbreaks (CAO) and warm air intrusions (WAI) over the key measurement sites of Svalbard and northern Norway. Thereby, meteorological and stable water isotope measurements have been performed at multiple sites both upstream and downstream of the CAOs and WAIs. The Lagrangian model FLEXPART has been run with the input data from the regional convection-permitting numerical weather prediction model AROME Arctic at 2.5 km resolution to investigate transport patterns. The combination of observations and model simulations allows us to quantify the connection between source and sink for different weather systems, as well as the link between large-scale transport and stable water isotopes. Findings will lead to a better understanding of processes in the water cycle and the degree of conservation of isotopic signals during transport. This study may also serve as a guideline on how to evaluate the performance of Lagrangian transport models using stable water isotope measurements, and on how to detect constraints for quantifying the transport route and evaporation source from stable water isotope measurements for future work, including an aircraft campaign planned in 2021.</p>

Climatic and associated atmospheric water cycle changes over the Xinjiang, China

2020 ◽  
Vol 585 ◽  
pp. 124823 ◽  
Author(s):  
Junqiang Yao ◽  
Yaning Chen ◽  
Yong Zhao ◽  
Xuefeng Guan ◽  
Weiyi Mao ◽  
...  
Keyword(s):  
Water Cycle ◽  
Atmospheric Water

scholarly journals A GCM study of the response of the atmospheric water cycle of West Africa and the Atlantic to Saharan dust radiative forcing

2009 ◽  
Vol 27 (10) ◽  
pp. 4023-4037 ◽  
Author(s):  
K. M. Lau ◽  
K. M. Kim ◽  
Y. C. Sud ◽  
G. K. Walker
Keyword(s):  
West Africa ◽  
Radiative Forcing ◽  
Large Scale ◽  
Water Cycle ◽  
Deep Convection ◽  
Saharan Dust ◽  
Caribbean Region ◽  
Atmospheric Water ◽  
The West ◽  
Dust Layer

Abstract. The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerly flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer over the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0.95 or higher.

Estimation of fine-scale relative humidity profiles: an issue for understanding the atmospheric water cycle

2020 ◽  
Author(s):  
Veronique Michot ◽  
Helene Brogniez ◽  
Mathieu Vrac ◽  
Soulivanh Thao ◽  
Helene Chepfer ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Quantile Regression ◽  
Water Vapour ◽  
Climate Models ◽  
Water Cycle ◽  
Skill Score ◽  
Horizontal Resolution ◽  
Atmospheric Water ◽  
Global Knowledge ◽  
Humidity Profiles

<p>The multi-scale interactions at the origin of the links between clouds and water vapour are essential for the Earth's energy balance and thus the climate, from local to global. Knowledge of the distribution and variability of water vapour in the troposphere is indeed a major issue for the understanding of the atmospheric water cycle. At present, these interactions are poorly known at regional and local scales, i.e. within 100km, and are therefore poorly represented in numerical climate models. This is why we have sought to predict cloud scale relative humidity profiles in the intertropical zone, using a non-parametric statistical downscaling method called quantile regression forest. The procedure includes co-located data from 3 satellites: CALIPSO lidar and CloudSat radar, used as predictors and providing cloud properties at 90m and 1.4km horizontal resolution respectively; SAPHIR data used as a predictor and providing relative humidity at an initial horizontal resolution of 10km. Quantile regression forests were used to predict relative humidity profiles at the CALIPSO and CloudSat scales. These predictions are able to reproduce a relative humidity variability consistent with the cloud profiles and are confirmed by values of coefficients of determination greater than 0.7, relative to observed relative humidity, and Continuous Rank Probability Skill Score between 0 and 1, relative to climatology. Lidar measurements from the NARVAL 1&2 campaigns and radiosondes from the EUREC4A campaigns were also used to compare Relative Humidity profiles at the SAPHIR scale and at the scale of forest regression prediction by quantile regression.</p>

A Method for Direct Assessment of the “Non Rainfall” Atmospheric Water Cycle: Input and Evaporation From the Soil

2011 ◽  
Vol 169 (5-6) ◽  
pp. 847-857 ◽  
Author(s):  
Kudzai Farai Kaseke ◽  
Anthony J. Mills ◽  
Roger Brown ◽  
Karen J. Esler ◽  
Johannes. R. Henschel ◽  
...  
Keyword(s):  
Water Cycle ◽  
Atmospheric Water ◽  
Direct Assessment

scholarly journals Developing a western Siberia reference site for tropospheric water vapour isotopologue observations obtained by different techniques (in situ and remote sensing)

2014 ◽  
Vol 14 (12) ◽  
pp. 5943-5957 ◽  
Author(s):  
K. Gribanov ◽  
J. Jouzel ◽  
V. Bastrikov ◽  
J.-L. Bonne ◽  
F.-M. Breon ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Vapour ◽  
General Circulation ◽  
Western Siberia ◽  
Water Cycle ◽  
General Circulation Models ◽  
Forest Site ◽  
Atmospheric Water ◽  
Local Measurements

Abstract. Water stable isotopologues provide integrated tracers of the atmospheric water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. Novel remote sensing and in situ measuring techniques have recently offered opportunities for monitoring atmospheric water vapour isotopic composition. Recently developed infrared laser spectrometers allow for continuous in situ measurements of surface water vapour δDv and δ18Ov. So far, very few intercomparisons of measurements conducted using different techniques have been achieved at a given location, due to difficulties intrinsic to the comparison of integrated with local measurements. Nudged simulations conducted with high-resolution isotopically enabled general circulation models (GCMs) provide a consistent framework for comparison with the different types of observations. Here, we compare simulations conducted with the ECHAM5-wiso model with two types of water vapour isotopic data obtained during summer 2012 at the forest site of Kourovka, western Siberia: hourly ground-based FTIR total atmospheric columnar δDv amounts, and in situ hourly Picarro δDv measurements. There is an excellent correlation between observed and predicted δDv at surface while the comparison between water column values derived from the model compares well with FTIR estimates.

scholarly journals Measuring variations of δ<sup>18</sup>O and δ<sup>2</sup>H in atmospheric water vapour using laser spectroscopy: an instrument characterisation study

2012 ◽  
Vol 5 (1) ◽  
pp. 1597-1655 ◽  
Author(s):  
F. Aemisegger ◽  
P. Sturm ◽  
P. Graf ◽  
H. Sodemann ◽  
S. Pfahl ◽  
...  
Keyword(s):  
Water Vapour ◽  
Laboratory Experiments ◽  
Water Cycle ◽  
Field Measurements ◽  
Detailed Knowledge ◽  
Spectroscopic Techniques ◽  
Mixing Ratio ◽  
Atmospheric Water ◽  
Uncertainty Estimates ◽  
Laser Spectroscopic

Abstract. Variations of stable water isotopes in water vapour have become measurable at a measurement frequency of about 1 Hz in recent years using novel laser spectroscopic techniques. This enables us to perform continuous measurements for process-based investigations of the atmospheric water cycle at the time scales relevant for synoptic meteorology. An important prerequisite for the interpretation of data from automated field measurements lasting for several weeks or months is a detailed knowledge about instrument properties and the sources of measurement uncertainty. We present here a comprehensive characterisation and comparison study of two commercial laser spectroscopic systems based on cavity ring-down spectroscopy (Picarro) and off-axis integrated cavity output spectroscopy (Los Gatos Research). The uncertainty components of the measurements were first assessed in laboratory experiments, focussing on the effects of (i) water vapour mixing ratio, (ii) measurement stability, (iii) uncertainties due to calibration and (iv) response times of the isotope measurements due to adsorption-desorption processes on the tubing and measurement cavity walls. Based on the experience from our laboratory experiments we set up a one-week field campaign for comparing measurements of the ambient isotope signals of the two laser spectroscopic systems. The optimal calibration strategy determined for both instruments was applied as well as the correction functions for water vapour mixing ratio effects. The root mean square difference between the isotope signals from the two instruments during the field deployment was 2.3‰ for δ2H, 0.5‰ for δ18O and 3.1‰ for deuterium excess. These uncertainty estimates from field measurements compare well to those found in the laboratory experiments. The present quality of measurements from laser spectroscopic instruments combined with a calibration system opens new possibilities for investigating the atmospheric water cycle and the land-atmosphere moisture fluxes.

scholarly journals Climate change assessment in Asian Water Cycle Initiative (AWCI) river basins

2013 ◽  
Vol 3 (1) ◽  
pp. 25-35
Author(s):  
Toshio Koike ◽  
Petra Koudelova ◽  
Patricia Ann Jaranilla-(Sanchez ◽  
Cho Thanda Nyunt ◽  
Sixto Durran-(Ballen
Keyword(s):  
Climate Change ◽  
Water Cycle ◽  
River Basins ◽  
Change Assessment ◽  
Climate Change Assessment ◽  
Asian Water
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