scholarly journals New Aura Microwave Limb Sounder observations of BrO and implications for Br<sub>y</sub>

2012 ◽  
Vol 5 (7) ◽  
pp. 1741-1751 ◽  
Author(s):  
L. Millán ◽  
N. Livesey ◽  
W. Read ◽  
L. Froidevaux ◽  
D. Kinnison ◽  
...  
Keyword(s):  
Error Analysis ◽  
Systematic Error ◽  
State Of The Art ◽  
Numerical Models ◽  
Inversion Algorithm ◽  
Broad Agreement ◽  
Atmospheric State

Abstract. This paper introduces a new inversion algorithm for retrievals of stratospheric BrO from the Aura Microwave Limb Sounder. This version is based on the algorithm described by Livesey et al. (2006a) but uses a more realistic atmospheric state to constrain the retrieval. A description of the methodology and an error analysis are presented. Single daily profile precision uncertainty, when taking the ascending-descending (day-night) difference, was found to be up to 40 pptv while systematic error biases were estimated to be less than about 3 pptv. Monthly mean comparisons show broad agreement with other measurements as well as with state-of-the-art numerical models. We infer a 2005 yearly total inorganic Bry using the measured MLS BrO to be 20.3 ± 4.5 pptv, which implies a contribution from very short lived substances to the stratospheric bromine budget of 5 ± 4.5 pptv.

scholarly journals New Aura Microwave Limb Sounder observations of BrO and implications for Br<sub>y</sub>

2012 ◽  
Vol 5 (1) ◽  
pp. 325-350
Author(s):  
L. Millán ◽  
N. Livesey ◽  
W. Read ◽  
L. Froidevaux ◽  
D. Kinnison ◽  
...  
Keyword(s):  
Error Analysis ◽  
Systematic Error ◽  
Pressure Range ◽  
Lower Stratosphere ◽  
State Of The Art ◽  
Numerical Models ◽  
Vertical Profiles ◽  
Inversion Algorithm ◽  
Lower Altitude ◽  
Broad Agreement

Abstract. This paper introduces a new inversion algorithm for retrievals of stratospheric BrO from the Aura Microwave Limb Sounder. This version is based on the algorithm described by Livesey et al. (2006a) but designed to reduce a large bias presented in the previous MLS BrO datasets in the lower stratosphere and, therefore, to increase its useable pressure range. In this new version, vertical profiles of BrO were obtained in the 100 to 4.6 hPa pressure range extending the lower altitude limit of the MLS retrievals. A description of the retrieval methodology and an error analysis are presented. Single daily profile precision, when taking the ascending-descending (day-night) difference, was found to be up to 40 pptv while systematic error biases were estimated to be less than about 3 pptv. Monthly mean comparisons show broad agreement with other measurements as well as with state-of-the-art numerical models. We infer total inorganic Bry using the measured MLS BrO to be 20.3 ± 4.5 pptv, which implies a contribution from Very Short Lived Substances to the stratospheric bromine budget of ∼5 ± 4.5 pptv.

scholarly journals Fengyun Meteorological Satellite Products for Earth System Science Applications

2021 ◽  
Author(s):  
Di Xian ◽  
Peng Zhang ◽  
Ling Gao ◽  
Ruijing Sun ◽  
Haizhen Zhang ◽  
...  
Keyword(s):  
Data Sharing ◽  
Satellite Data ◽  
Prediction Models ◽  
Weather Forecasting ◽  
Numerical Models ◽  
Weather Prediction ◽  
Vegetation Indices ◽  
Open Data ◽  
Earth System ◽  
Inversion Algorithm

AbstractFollowing the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the Fengyun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.

Systematic Error Analysis for the Enhancement of Biometric Systems Using Soft Biometrics

2012 ◽  
Vol 19 (12) ◽  
pp. 833-836 ◽  
Author(s):  
Anastasios Drosou ◽  
D. Tzovaras ◽  
K. Moustakas ◽  
M. Petrou
Keyword(s):  
Error Analysis ◽  
Systematic Error ◽  
Soft Biometrics ◽  
Biometric Systems

scholarly journals Error analysis for the lidar backward inversion algorithm

1999 ◽  
Vol 38 (21) ◽  
pp. 4461 ◽  
Author(s):  
Francesc Rocadenbosch ◽  
Adolfo Comerón
Keyword(s):  
Error Analysis ◽  
Inversion Algorithm

scholarly journals A Review of Hydraulic Fracturing Simulation

2021 ◽  
Author(s):  
Bin Chen ◽  
Beatriz Ramos Barboza ◽  
Yanan Sun ◽  
Jie Bai ◽  
Hywel R Thomas ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
State Of The Art ◽  
Numerical Models ◽  
Gas Production ◽  
Physical Processes ◽  
Horizontal Drilling ◽  
Improve Treatment ◽  
Multi Stage ◽  
Pros And Cons ◽  
Treatment Designs

AbstractAlong with horizontal drilling techniques, multi-stage hydraulic fracturing has improved shale gas production significantly in past decades. In order to understand the mechanism of hydraulic fracturing and improve treatment designs, it is critical to conduct modelling to predict stimulated fractures. In this paper, related physical processes in hydraulic fracturing are firstly discussed and their effects on hydraulic fracturing processes are analysed. Then historical and state of the art numerical models for hydraulic fracturing are reviewed, to highlight the pros and cons of different numerical methods. Next, commercially available software for hydraulic fracturing design are discussed and key features are summarised. Finally, we draw conclusions from the previous discussions in relation to physics, method and applications and provide recommendations for further research.

2-D and 3-D resistivity image reconstruction using crosshole data

Geophysics ◽  
1992 ◽  
Vol 57 (10) ◽  
pp. 1270-1281 ◽  
Author(s):  
Hiromasa Shima
Keyword(s):  
Field Test ◽  
Numerical Models ◽  
Electrical Potential ◽  
Nonlinear Least Squares ◽  
Three Dimensions ◽  
Inversion Method ◽  
Good Resolution ◽  
Inversion Algorithm ◽  
Linear Inversion ◽  
Resistivity Model

Theoretical changes in the distribution of electrical potential near subsurface resistivity anomalies have been studied using two resistivity models. The results suggest that the greatest response from such anomalies can be observed with buried electrodes, and that the resistivity model of a volume between boreholes can be accurately reconstructed by using crosshole data. The distributive properties of crosshole electrical potential data obtained by the pole‐pole array method have also been examined using the calculated partial derivative of the observed apparent resistivity with respect to a small cell within a given volume. The results show that for optimum two‐dimensional (2-D) and three‐dimensional (3-D) target imaging, in‐line data and crossline data should be combined, and an area outside the zone of exploration should be included in the analysis. In this paper, the 2-D and 3-D resistivity images presented are reconstructed from crosshole data by the combination of two inversion algorithms. The first algorithm uses the alpha center method for forward modeling and reconstructs a resistivity model by a nonlinear least‐squares inversion. Alpha centers express a continuously varying resistivity model, and the distribution of the electrical potential from the model can be calculated quickly. An initial general model is determined by the resistivity backprojection technique (RBPT) prior to the first inversion step. The second process uses finite elements and a linear inversion algorithm to improve the resolution of the resistivity model created by the first step. Simple 2-D and 3-D numerical models are discussed to illustrate the inversion method used in processing. Data from several field studies are also presented to demonstrate the capabilities of using crosshole resistivity exploration techniques. The numerical experiments show that by using the combined reconstruction algorithm, thin conductive layers can be imaged with good resolution for 2-D and 3-D cases. The integration of finite‐element computations is shown to improve the image obtained by the alpha center inversion process for 3-D applications. The first field test uses horizontal galleries to evaluate complex 2-D features of a zinc mine. The second field test illustrates the use of three boreholes at a dam site to investigate base rock features and define the distribution of an altered zone in three dimensions.

scholarly journals FRF WAVE TEST BED AND BATHYMETRY INVERSION

2017 ◽  
pp. 22 ◽  
Author(s):  
Jane McKee Smith ◽  
Spicer Bak ◽  
Tyler Hesser ◽  
Mary A. Bryant ◽  
Chris Massey
Keyword(s):  
Numerical Models ◽  
Field Research ◽  
Wave Model ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Test Bed ◽  
Inversion Algorithm ◽  
Us Army ◽  
Spectral Wave Model ◽  
Limited Application

An automated Coastal Model Test Bed has been built for the US Army Corps of Engineers Field Research Facility to evaluate coastal numerical models. In October of 2015, the test bed was expanded during a multi-investigator experiment, called BathyDuck, to evaluate two bathymetry sources: traditional survey data and bathymetry generated through the cBathy inversion algorithm using Argus video measurements. Comparisons were made between simulations using the spectral wave model STWAVE with half-hourly cBathy bathymetry and the more temporally sparse surveyed bathymetry. The simulation results using cBathy bathymetry were relatively close to those using the surveyed bathymetry. The largest differences were at the shallowest gauges within 250 m of the coast, where wave model normalized root-mean-square was approximately twice are large using the cBathy bathymetry. The nearshore errors using the cBathy input were greatest during events with wave height greater than 2 m. For this limited application, the Argus cBathy algorithm proved to be a suitable bathymetry input for nearshore wave modeling. cBathy bathymetry was easily incorporated into the modeling test bed and had the advantage of being updated on approximately the same temporal scale as the other model input conditions. cBathy has great potential for modeling applications where traditional surveys are sparse (seasonal or yearly).

Sign in / Sign up

Export Citation Format

Share Document