scholarly journals A Simple Method of Deriving Three-Dimensional Temperature Fields Using Remotely Sensed and In Situ Data for Application to Numerical Hydrodynamic Models of Estuaries and Bays

2004 ◽  
Vol 21 (7) ◽  
pp. 1044-1058
Author(s):  
Timothy R. Keen ◽  
Richard W. Gould ◽  
Jean-Francois Cayula ◽  
Walton E. McBride ◽  
John P. Blaha ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Remotely Sensed ◽  
Temperature Fields ◽  
Hydrodynamic Models ◽  
Simple Method ◽  
In Situ Data

scholarly journals Parameterizing the impact of vegetated urban canopies on wind and temperature fields by using a simple nudging method

2021 ◽  
Author(s):  
Ge Cheng ◽  
David Grawe ◽  
K. Heinke Schlünzen
Keyword(s):  
Mesoscale Model ◽  
Three Dimensional ◽  
Urban Canopy ◽  
Temperature Fields ◽  
Simple Method ◽  
Local Climate ◽  
Local Climate Zones ◽  
Urban Canopy Parameterizations ◽  
The Impact ◽  
Nudging Method

<p>Nudging is a simple method that aims to dynamically adjust the model toward the observations by including an additional feedback term in the model governing equation. This method is widely applied in data assimilation due to its simple implementation and reasonable model results. The basic concept of nudging is similar to that of urban canopy parameterization, in which additional terms are usually added in the conservation equations of momentum and energy aiming to simulate the canopy effects. However, few studies have investigated the implementation of nudging methods in urban canopy parameterizations. In this study we developed a multi-layer urban canopy parameterization (UCP) by using a nudging approach to represent the impacts of vegetated urban canopies on temperatures and winds in mesoscale models.</p><p>The difficulty of developing UCP by using a nudging method lies in defining appropriate values for the nudging coefficients and the forcing fields (e.g. indoor temperature fields for temperature nudging). To determine nudging coefficients, we use three major urban canopy morphological parameters: building height, frontal area density and building density. The ranges of these parameters are taken from the values for the Local Climate Zones datasets, in our case for the city of Hamburg. The UCP is employed in the three -dimensional atmospheric mesoscale model METRAS. Results show that this UCP can well simulate wind-blocking effects induced from obstacles as buildings and trees and urban heat island phenomenon for cities. Thus, nudging is an efficient and effective method that can be used for urban canopy parameterizations. However, as well known for nudging, it is not conserving energy. Therefore, we investigated the energy loss by tracking the reduced kinetic energy and internal energy. The UCP and model results will be presented.</p>

In Situ Visualization of Layer Transitions during Convective Self-Assembly in a Sessile Drop

2007 ◽  
Vol 31 ◽  
pp. 117-119
Author(s):  
Li Gao ◽  
Qing Feng Yan ◽  
C.C. Wong ◽  
Yet Ming Chiang
Keyword(s):  
Self Assembly ◽  
Sessile Drop ◽  
Three Dimensional ◽  
Colloidal Crystals ◽  
Layer Transition ◽  
Simple Method ◽  
Colloidal Spheres ◽  
In Situ Visualization ◽  
Set Up

Convective self-assembly of colloidal spheres provides a simple method for fabricating two and three dimensional colloidal crystals. In this work, we investigated the layer transitions phenomena during colloidal self-assembly in a sessile drop by using an in-situ videoscopic set-up. The effects of surface charge, colloidal concentration, and surfactant additions were examined. The results show that the chemical environment plays an important role in colloidal self-assembly. In the case of ordered growth, different layer transition phenomena were observed when the colloidal concentration is different.

scholarly journals Three-Dimensional Evolution of Large-Amplitude Internal Waves in the Strait of Gibraltar

2009 ◽  
Vol 39 (9) ◽  
pp. 2230-2246 ◽  
Author(s):  
Vasiliy Vlasenko ◽  
Jose C. Sanchez Garrido ◽  
Nataliya Stashchuk ◽  
Jesus Garcia Lafuente ◽  
Miguel Losada
Keyword(s):  
Internal Waves ◽  
Large Amplitude ◽  
Wave Train ◽  
Three Dimensional ◽  
Regular Structure ◽  
Strait Of Gibraltar ◽  
Multiple Reflections ◽  
In Situ Data ◽  
Scattered Energy

Abstract The modeling of large-amplitude internal waves (LAIWs) propagating in the Strait of Gibraltar is carried out using a fully nonlinear nonhydrostatic numerical model. The focus of the modeling efforts was on three-dimensional peculiarities of LAIW evolution, namely, cross-strait variability, interaction with lateral boundaries (including wave breaking and water mixing), radiation of secondary waves from orographic features, and interaction of secondary scattered internal waves. The along-channel propagation of packets of LAIWs reveals remarkable three-dimensional behavior. Due to the Coriolis force and multiple reflections from the lateral boundaries, the largest leading LAIW loses its energy much faster than that in the packet tail, which captures the scattered energy from the leading wave as it propagates and grows in amplitude. As a result of the energy transfer, the initially rank-ordered wave packet loses its regular structure to evolve into a non-rank-ordered wave train. In situ data collected in the eastern part of the Strait of Gibraltar confirm the idea that the non-rank-ordered structure is a common feature of internal wave packets emerging from the strait into the Alboran Sea.

scholarly journals A framework for comparing remotely sensed and in-situ CO<sub>2</sub> concentrations

2008 ◽  
Vol 8 (1) ◽  
pp. 1549-1588 ◽  
Author(s):  
R. Macatangay ◽  
T. Warneke ◽  
C. Gerbig ◽  
S. Körner ◽  
R. Ahmadov ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Transport Model ◽  
Remotely Sensed ◽  
Infrared Spectrometry ◽  
Remotely Sensed Data ◽  
Solar Absorption ◽  
Mixing Ratios ◽  
In Situ Data ◽  
Global Calibration

Abstract. A framework that allows validating CO2 column averaged volume mixing ratios (VMRs) retrieved from ground-based solar absorption measurements using Fourier transform infrared spectrometry (FTS) against measurements made in-situ (such as from aircrafts and tall towers) has been developed. Since in-situ measurements are done frequently and at high accuracy on the global calibration scale, linking this scale with FTS total column retrievals ultimately provides a calibration scale for remote sensing. FTS, tower and aircraft data were analyzed from measurements during the CarboEurope Regional Experiment Strategy (CERES) from May to June 2005 in Biscarrosse, France. Carbon dioxide VMRs from the MetAir Dimona aircraft, the TM3 global transport model and Observations of the Middle Stratosphere (OMS) balloon based experiments were combined and integrated to compare with FTS measurements. The comparison agrees fairly well with differences resulting from the spatial variability of CO2 around the FTS as measured by the aircraft. Additionally, the Stochastic Time Inverted Lagrangian Transport (STILT) model served as a "transfer standard" between the in-situ data measured at a co-located tower and the remotely sensed data from the FTS. The variability of carbon dioxide VMRs was modeled well by STILT with differences coming partly from uncertainties in the spatial variation of carbon dioxide.

scholarly journals Seven Years of SMOS Sea Surface Salinity at High Latitudes: Variability in Arctic and Sub-Arctic Regions

2018 ◽  
Vol 10 (11) ◽  
pp. 1772 ◽  
Author(s):  
Estrella Olmedo ◽  
Carolina Gabarró ◽  
Verónica González-Gambau ◽  
Justino Martínez ◽  
Joaquim Ballabrera-Poy ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Remotely Sensed ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
The Arctic ◽  
Surface Salinity ◽  
In Situ Data ◽  
Arctic Regions ◽  
The Difference

This paper aims to present and assess the quality of seven years (2011–2017) of 25 km nine-day Soil Moisture and Ocean Salinity (SMOS) Sea Surface Salinity (SSS) objectively analyzed maps in the Arctic and sub-Arctic oceans ( 50 ∘ N– 90 ∘ N). The SMOS SSS maps presented in this work are an improved version of the preliminary three-year dataset generated and freely distributed by the Barcelona Expert Center. In this new version, a time-dependent bias correction has been applied to mitigate the seasonal bias that affected the previous SSS maps. An extensive database of in situ data (Argo floats and thermosalinograph measurements) has been used for assessing the accuracy of this product. The standard deviation of the difference between the new SMOS SSS maps and Argo SSS ranges from 0.25 and 0.35. The major features of the inter-annual SSS variations observed by the thermosalinographs are also captured by the SMOS SSS maps. However, the validation in some regions of the Arctic Ocean has not been feasible because of the lack of in situ data. In those regions, qualitative comparisons with SSS provided by models and the remotely sensed SSS provided by Aquarius and SMAP have been performed. Despite the differences between SMOS and SMAP, both datasets show consistent SSS variations with respect to the model and the river discharge in situ data, but present a larger dynamic range than that of the model. This result suggests that, in those regions, the use of the remotely sensed SSS may help to improve the models.

Modeling of channel processes in large rivers with the use of field data

2021 ◽  
Vol 9 (1) ◽  
pp. 87-102
Author(s):  
A.T. Zinoviev ◽  
◽  
A.V. Dyachenko ◽  
K.B. Koshelev ◽  
K.V. Marusin ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Anthropogenic Impacts ◽  
Three Dimensional ◽  
Large Rivers ◽  
Observation Data ◽  
Channel Processes ◽  
Channel Deformations ◽  
Study Section ◽  
In Situ Data

The paper deals with mathematical description of channel processes occurring in long sections of large rivers with a complex morphometry. To forecast negative manifestations of channel deformations, a computer model of river sediment transport in the study section is proposed. It is based on a three-dimensional (3D) / two-dimensional horizontal (2DH) flow model, a 2DH model of bed sediment transport and observation data. Comparative analysis of simulation results of channel processes in the Ob river section at the Barnaul water intakes and in situ data makes it possible to evaluate forecast capabilities of the designed model, in particular, for quantitative assessment of changes in channel topography of the study section caused by natural and anthropogenic impacts.

The MLT distribution and detailed structure of ring current:  MMS observations

2021 ◽  
Author(s):  
Xin Tan ◽  
Malcolm Dunlop ◽  
Xiangcheng Dong ◽  
Yanyan Yang ◽  
Christopher Russell
Keyword(s):  
Current Density ◽  
Large Scale ◽  
Ring Current ◽  
Current System ◽  
Radial Profile ◽  
Three Dimensional ◽  
Current Density Distribution ◽  
Magnetic Storms ◽  
In Situ Data

&lt;p&gt;The ring current is an important part of the large-scale magnetosphere-ionosphere current system; mainly concentrated in the equatorial plane, between 2-7 R&lt;sub&gt;E&lt;/sub&gt;, and strongly ordered between &amp;#177; 30 &amp;#176; latitude. The morphology of ring current directly affects the geomagnetic field at low to middle latitudes. Rapid changes in ring current densities can occur during magnetic storms/sub-storms. Traditionally, the Dst index is used to characterize the intensity of magnetic storms and to reflect the variation of ring current intensity, but this index does not reflect the MLT distribution of ring current. In fact, the ring current has significant variations with MLT, depending on geomagnetic activity, due to the influence of multiple factors; such as, the partial ring current, region 1/region 2 field-aligned currents, the magnetopause current and sub-storm cycle (magnetotail current). The form of the ring current has been inferred from the three-dimensional distribution of ion differential fluxes from neutral atom imaging; however, this technique can not directly obtain the current density distribution (as can be obtained using multi-spacecraft in situ data). Previous in situ estimates of current density have used: Cluster, THEMIS and other spacecraft groups to study the distribution of the ring current for limited ranges of either radial profile, or MLT and MLAT variations. Here, we report on an extension to these studies using FGM data from MMS obtained during the period September 1, 2015 to December 31, 2016, when the MMS orbit and configuration provided good coverage. We employ the curlometer method to calculate the current density, statistically, to analysis the MLT distribution according to different geomagnetic conditions. Our results show the clear asymmetry of the ring current and its different characteristics under different geomagnetic conditions.&lt;/p&gt;

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