A New Method for Gas-Flux Calculation in Atmospheric Boundary Layer Based on the Active Detection of LiDAR System

2021 ◽  
Author(s):  
Rong Ma ◽  
Wei Yao ◽  
Meng Lu ◽  
Zhitong Yu
Keyword(s):  
Boundary Layer ◽  
Carbon Cycle ◽  
Atmospheric Boundary Layer ◽  
Atmospheric Stability ◽  
New Method ◽  
Earth System ◽  
Lidar System ◽  
Gas Flux ◽  
Flux Calculation ◽  
The Earth

<p>The Flux information based on momentum, energy and matter is an important link between different components of the earth system. Flux observation is of great significance for understanding the energy and matter exchange in each circle of the earth system, revealing the carbon cycle process at the same time. Fluxes between the atmosphere and the Earth's surface must pass through the atmospheric boundary layer and have considerable influence on the state of the atmospheric boundary layer. Therefore, the observation and analysis of vertical turbulent flux in the atmospheric boundary layer has become a hot topic of atmospheric research. Based on the development of turbulence theory, the method of calculating gas-flux in the atmospheric boundary layer is constantly improved. In recent years, with the development of lidar detection system, doppler lidar system and differential absorption lidar system have also been effectively used to measure the mean wind speed and small-scale dynamic turbulence parameters, which can be applied to directly detect gas flux of the atmospheric boundary layer. For major scientific issues in the global carbon cycle and carbon emission reduction monitoring needs, this paper has developed a new method of gas-flux calculation of atmospheric boundary layer, while obtaining the wind profile information and gas concentration profile information at the same time and at the same place by the detection of lidar system. This method calculates flux takes into account the atmospheric stability judgment, surface friction velocity and the Monin-Obukhov stability parameter based on the turbulent transport theory of atmospheric boundary layer. It can quickly and effectively realize the active remote sensing detection of the gas flux information of atmospheric boundary layer under different atmospheric stability conditions，which has been proved to be effective and accurate by comparing with other gas-flux data.</p>

scholarly journals Reviews and syntheses: Flying the satellite into your model: on the role of observation operators in constraining models of the Earth system and the carbon cycle

2017 ◽  
Vol 14 (9) ◽  
pp. 2343-2357 ◽  
Author(s):  
Thomas Kaminski ◽  
Pierre-Philippe Mathieu
Keyword(s):  
Data Assimilation ◽  
Carbon Cycle ◽  
Automatic Differentiation ◽  
Satellite Observations ◽  
Spectral Radiance ◽  
Special Focus ◽  
Earth System ◽  
The Earth ◽  
Retrieval Scheme

Abstract. The vehicles that fly the satellite into a model of the Earth system are observation operators. They provide the link between the quantities simulated by the model and the quantities observed from space, either directly (spectral radiance) or indirectly estimated through a retrieval scheme (biogeophysical variables). By doing so, observation operators enable modellers to properly compare, evaluate, and constrain their models with the model analogue of the satellite observations. This paper provides the formalism and a few examples of how observation operators can be used in combination with data assimilation techniques to better ingest satellite products in a manner consistent with the dynamics of the Earth system expressed by models. It describes commonalities and potential synergies between assimilation and classical retrievals. This paper explains how the combination of observation operators and their derivatives (linearizations) form powerful research tools. It introduces a technique called automatic differentiation that greatly simplifies both the development and the maintenance of code for the evaluation of derivatives. Throughout this paper, a special focus lies on applications to the carbon cycle.

scholarly journals Soil Moisture-Boundary Layer Feedbacks on the Loess Plateau in China Using Radiosonde Data with 1-D Atmospheric Boundary Layer Model

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1619
Author(s):  
Yingsai Ma ◽  
Xianhong Meng ◽  
Yinhuan Ao ◽  
Ye Yu ◽  
Guangwei Li ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Soil Moisture ◽  
Atmospheric Boundary Layer ◽  
Loess Plateau ◽  
Atmospheric Stability ◽  
Heat Fluxes ◽  
Radiosonde Data ◽  
Atmospheric Conditions ◽  
The Loess Plateau ◽  
The Impact

The Loess Plateau is one land-atmosphere coupling hotspot. Soil moisture has an influence on atmospheric boundary layer development under specific early-morning atmospheric thermodynamic structures. This paper investigates the sensitivity of atmospheric convection to soil moisture conditions over the Loess Plateau in China by using the convective triggering potential (CTP)—humidity index (HIlow) framework. The CTP indicates atmospheric stability and the HIlow indicates atmospheric humidity in the low-level atmosphere. By comparing the model outcomes with the observations, the one-dimensional model achieves realistic daily behavior of the radiation and surface heat fluxes and the mixed layer properties with appropriate modifications. New CTP-HIlow thresholds for soil moisture-atmosphere feedbacks are found in the Loess Plateau area. By applying the new thresholds with long-time scales sounding data, we conclude that negative feedback is dominant in the north and west portion of the Loess Plateau; positive feedback is predominant in the south and east portion. In general, this framework has predictive significance for the impact of soil moisture on precipitation. By using this new CTP-HIlow framework, we can determine under what atmospheric conditions soil moisture can affect the triggering of precipitation and under what atmospheric conditions soil moisture has no influence on the triggering of precipitation.

Numerical Study of Yawed Wind Turbine Under Unstable Atmospheric Boundary Layer Flows

2020 ◽  
Author(s):  
Dezhi Wei ◽  
Decheng Wan
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Wind Turbine ◽  
Numerical Study ◽  
Atmospheric Stability ◽  
Wind Farms ◽  
Total Power ◽  
Turbulent Structures ◽  
Ambient Turbulence ◽  
Turbine Wake

Abstract Turbine-wake interactions among wind turbine array significantly affect the efficiency of wind farms. Yaw angle control is one of the potential ways to increase the total power generation of wind plants, but the sensitivity of such control strategy to atmospheric stability is rarely studied. In the present work, large-eddy simulation of a two-turbine configuration under convective atmospheric boundary layer is performed, with different yaw angles for the front one, the effect of turbine induced forces on the flow field is modeled by actuator line. Emphasis is placed on wake characteristics and aerodynamic performance. Simulation results reveal that atmospheric stability has a considerable impact on the behavior of wind turbine, wake deflection on the horizontal hub height plane for yawed wind turbine is relatively small, compared with the result of the empirical wake model proposed for wind turbine operating in the neutral stratification, which is attributed to the higher ambient turbulence intensity and large variance of wind direction in the convective condition. And associated with the smaller wake deflection, the total power production does not increase as expected when yawing the upstream turbine. In addition, due to the existence of great quantities of disorganized coherent turbulent structures in the unstable condition, the yaw bearing moment experienced by the downstream wind turbine increases dramatically, even if the rotor plane of the first turbine is perpendicular to the inflow direction.

scholarly journals Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing

2017 ◽  
Author(s):  
Steven J. Lade ◽  
Jonathan F. Donges ◽  
Ingo Fetzer ◽  
John M. Anderies ◽  
Christian Beer ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Model Test ◽  
Global Climate ◽  
Earth System ◽  
Planetary Boundaries ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
The Earth ◽  
Analytical Expressions ◽  
Earth System Models

Abstract. Changes to climate-carbon cycle feedbacks may significantly affect the Earth System’s response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth System Models (ESMs). Here, we construct a stylized global climate-carbon cycle model, test its output against complex ESMs, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon-cycle feedbacks and the operation of the carbon cycle. We use our results to analytically study the relative strengths of different climate-carbon cycle feedbacks and how they may change in the future, as well as to compare different feedback formalisms. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the Planetary Boundaries, that are currently too uncertain to be included in complex ESMs.

scholarly journals Large-Eddy Simulations of Stability-Varying Atmospheric Boundary Layer Flow over Isolated Buildings

2021 ◽  
Author(s):  
Hyeyum Hailey Shin ◽  
Domingo Muñoz-Esparza ◽  
Jeremy A. Sauer ◽  
Matthias Steiner
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Atmospheric Stability ◽  
Lateral Side ◽  
Mean Flow ◽  
Turbulence Scale ◽  
Advection Scheme ◽  
Large Eddy ◽  
Flow Features ◽  
Induced Flow

AbstractThis study explores the response of flow around isolated cuboid buildings to variations in the incoming turbulence arising from changes in atmospheric boundary layer (ABL) stability using a building-resolving large-eddy simulation (LES) technique with explicit representation of building effects through an immersed body force method. An extensive suite of LES for a neutral ABL with different model resolution and advection scheme configurations reveals that at least 6, 12, and 24 grid points per building side are required in order to resolve building-induced vortex shedding, mean-flow features, and turbulence statistics, respectively, with an advection scheme of a minimum of third-order. Using model resolutions that meet this requirement, 21 building-resolving simulations are performed under varying atmospheric stability conditions, from weakly stable to convective ABLs, and for different building sizes (H), resulting in LABL/H ≈ 0.1 – 10, where LABL is the integral length scale of the incoming ABL turbulence. The building-induced flow features observed in the canonical neutral ABL simulation, e.g., the upstream horseshoe vortex and the downstream arch vortex, gradually weaken with increasing surface-driven convective instability due to the enhancement of background turbulent mixing. As a result, two local turbulence kinetic energy peaks on the lateral side of the building in non-convective cases are merged into a single peak in strong convective cases. By considering the ABL turbulence scale and building size altogether, it is shown that the building impact decreases with increasing LABL/H, as coherent turbulent structures in the ABL become more dominant over a building-induced flow response for LABL/H > 1.

High-resolution temperature and wind field observations in the atmospheric boundary layer

2020 ◽  
Author(s):  
Matthias Zeeman ◽  
Marwan Katurji ◽  
Tirtha Banerjee
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Land Surface ◽  
Wind Field ◽  
Single Point ◽  
Sonic Anemometer ◽  
Atmospheric Stability ◽  
Surface Boundary ◽  
Three Dimensional Model ◽  
Local Flow

<p>Do we get a better picture of the world around us if we simultaneously observe many aspects instead of a few? Dense sensing networks are an elaborate way to validate our representation of land surface boundary layer processes commonly derived from single point monitoring stations or a three-dimensional model world. More samples promise unique insights into interactions that occur at different scales, separated in space and time.</p><p>We present a combination of techniques that purvey a) observations of the temperature and wind field in high detail and b) the extraction of information about dynamic interactions near the surface. A field experiment was conducted in complex terrain, in which landscape features dramatically modulate local flow patterns and the atmospheric stability during summer days rapidly transitions on a diurnal scale and between locations. Wind and temperature were simultaneously observed using a network of Doppler lidar, sonic anemometer, fiber-optic temperature sensing (DTS) and thermal imaging velocimetry (TIV) instrumentation, centered around the TERENO/ICOS preAlpine grassland observatory station Fendt, Germany, during the ScaleX Campaigns (https://scalex.imk-ifu.kit.edu). Data analyses relied on signal decomposition and statistical clustering, aimed at the characterization of (non-)turbulent motions and their feedback on turbulent mixing near the surface. The combination of methods offered multiple levels of detail about the development and impact of organized structures in the atmospheric boundary layer.</p><p>The study shows that the exploration of novel micrometeorological and data sciences techniques helps advance our knowledge of fundamental aspects of atmospheric turbulence, and provides new avenues for theoretical and numerical studies of the atmospheric boundary layer.</p>

Modelling the global carbon cycle for the past and future evolution of the earth system

1999 ◽  
Vol 159 (1-4) ◽  
pp. 305-317 ◽  
Author(s):  
Siegfried Franck ◽  
Konrad Kossacki ◽  
Christine Bounama
Keyword(s):  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
Earth System ◽  
Future Evolution ◽  
The Past ◽  
The Earth ◽  
Global Carbon

scholarly journals On the turbulent structure of the marine atmospheric boundary layer from CBLAST Nantucket measurements

2013 ◽  
Vol 10 (3) ◽  
pp. 210-217
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Land Surface ◽  
Atmospheric Stability ◽  
Heat Fluxes ◽  
Turbulent Structure ◽  
Atmospheric Conditions ◽  
Turbulent Characteristics ◽  
Momentum Fluxes

In this work preliminary results on the characteristics of the turbulent structure of the Marine Atmospheric Boundary Layer (MABL) are presented. Measurements used here were conducted in the framework of the Coupled Boundary Layers Air-Sea Transfer Experiment in Low Wind (CBLAST-Low) project. A number of in situ (fast and slow sensors) and remote sensing (SODAR) instruments were deployed on the coast of Nantucket Island, MA, USA. Measurements of the mean wind, the variances of the three wind components, the atmospheric stability and the momentum fluxes from the acoustic radar (SODAR) revealed the variation of the depth, the turbulent characteristics, and the stability of the MABL in response to the background flow. More specifically, under light south-southwesterly winds, which correspond to the MABL wind directions, the atmosphere was very stable and low values of turbulence were observed. Under moderate to strong southwesterly flow, less stable and neutral atmospheric conditions appeared and the corresponding turbulent quantities were characterized by higher values. The SODAR measurements, with high temporal and spatial resolution, also indicated large magnitude of momentum fluxes at higher levels, presumably associated with the shear forcing near the developed low-level jet. The measurements from the in-situ instrumentation confirmed that the MABL typically has small negative momentum and sensible heat fluxes consistent with stable to neutral stratification while strong diurnal variations were typical for the land surface Atmospheric Boundary Layer (ABL). The developed internal ABL at the experimental site was in general less than 10m during the night and could reach 15m heights during the day, particularly under low-wind conditions.

Sign in / Sign up

Export Citation Format

Share Document