ATMOSPHERIC EMISSION AND THE NET RADIATION AT THE GROUND

Evapotranspiration (ET) and precipitation were measured during five summers (1989-1993 inclusive) at a subarctic forest site near Churchill, Manitoba, Canada. Mean daily ET varied from 2.14-3.18 mm d−1 during the five summers, while mean daily precipitation (P) ranged from 1.46-3.15 mm d−1. Yearly variability in summer ET was most influenced by availability of surface moisture, then by atmospheric conditions (i.e. temperature), and least of all by net radiation. In four of the five years total summer ET exceeded P resulting in significant soil water deficits and in the other year summer ET and P were similar in magnitude. The use of equilibrium evaporation (EE) as a predictor of ET was explored. Separate relationships between ET and EE were computed for all five years. Three statistically dissimilar groups of equations were found: 1989/1990, 1991/ 1992, and 1993. A single regression equation describing all years is presented.

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Emission Inventories and Particulate Matter Air Quality Modeling over the Pearl River Delta Region

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18084155 ◽

2021 ◽

Vol 18 (8) ◽

pp. 4155

Author(s):

Diogo Lopes ◽

Joana Ferreira ◽

Ka In Hoi ◽

Ka-Veng Yuen ◽

Kai Meng Mok ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Pearl River Delta ◽

Air Quality Modeling ◽

Pearl River ◽

Emission Inventories ◽

Atmospheric Emission ◽

The Pearl River Delta ◽

Quality Modeling ◽

The Pearl River

The Pearl River Delta (PRD) region is located on the southeast coast of mainland China and it is an important economic hub. The high levels of particulate matter (PM) in the atmosphere, however, and poor visibility have become a complex environmental problem for the region. Air quality modeling systems are useful to understand the temporal and spatial distribution of air pollution, making use of atmospheric emission data as inputs. Over the years, several atmospheric emission inventories have been developed for the Asia region. The main purpose of this work is to evaluate the performance of the air quality modeling system for simulating PM concentrations over the PRD using three atmospheric emission inventories (i.e., EDGAR, REAS and MIX) during a winter and a summer period. In general, there is a tendency to underestimate PM levels, but results based on the EDGAR emission inventory show slightly better accuracy. However, improvements in the spatial and temporal disaggregation of emissions are still needed to properly represent PRD air quality. This study’s comparison of the three emission inventories’ data, as well as their PM simulating outcomes, generates recommendations for future improvements to atmospheric emission inventories and our understanding of air pollution problems in the PRD region.

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Midwinter melts in the Canadian prairies: energy balance and hydrological effects

Hydrology and Earth System Sciences ◽

10.5194/hess-23-1867-2019 ◽

2019 ◽

Vol 23 (4) ◽

pp. 1867-1883 ◽

Cited By ~ 5

Author(s):

Igor Pavlovskii ◽

Masaki Hayashi ◽

Daniel Itenfisu

Keyword(s):

Surface Runoff ◽

Hydrological Cycle ◽

Remote Sensing Data ◽

Heat Fluxes ◽

Sensible Heat ◽

Net Radiation ◽

Present Climate ◽

Canadian Prairies ◽

Energy Inputs ◽

Hydrological Effects

Abstract. Snowpack accumulation and depletion are important elements of the hydrological cycle in the Canadian prairies. The surface runoff generated during snowmelt is transformed into streamflow or fills numerous depressions driving the focussed recharge of groundwater in this dry setting. The snowpack in the prairies can undergo several cycles of accumulation and depletion in a winter. The timing of the melt affects the mechanisms of snowpack depletion and their hydrological implications. The effects of midwinter melts were investigated at four instrumented sites in the Canadian prairies. Unlike net radiation-driven snowmelt during spring melt, turbulent sensible heat fluxes were the dominant source of energy inputs for midwinter melt occurring in the period with low solar radiation inputs. Midwinter melt events affect several aspects of hydrological cycle with lower runoff ratios than subsequent spring melt events, due to their role in the timing of the focussed recharge. Remote sensing data have shown that midwinter melt events regularly occur under the present climate throughout the Canadian prairies, indicating applicability of the study findings throughout the region.

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Optimal Calibration of Evaporation Models against Penman–Monteith Equation

Water ◽

10.3390/w13111484 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1484

Author(s):

Dagmar Dlouhá ◽

Viktor Dubovský ◽

Lukáš Pospíšil

Keyword(s):

Model Calibration ◽

Heat Storage ◽

Free Water ◽

Complex Model ◽

Model Parameters ◽

Net Radiation ◽

Statistical Measures ◽

Pit Lakes ◽

Evaporation Models ◽

Monteith Equation

We present an approach for the calibration of simplified evaporation model parameters based on the optimization of parameters against the most complex model for evaporation estimation, i.e., the Penman–Monteith equation. This model computes the evaporation from several input quantities, such as air temperature, wind speed, heat storage, net radiation etc. However, sometimes all these values are not available, therefore we must use simplified models. Our interest in free water surface evaporation is given by the need for ongoing hydric reclamation of the former Ležáky–Most quarry, i.e., the ongoing restoration of the land that has been mined to a natural and economically usable state. For emerging pit lakes, the prediction of evaporation and the level of water plays a crucial role. We examine the methodology on several popular models and standard statistical measures. The presented approach can be applied in a general model calibration process subject to any theoretical or measured evaporation.

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