scholarly journals Snow-load excitation of the Earth's annual wobble

1988 ◽  
Vol 128 ◽  
pp. 373-380 ◽  
Author(s):  
B. Fong Chao ◽  
William P. O'Connor ◽  
Alfred T. C. Chang
Keyword(s):  
Rotation Axis ◽  
Microwave Remote Sensing ◽  
Seasonal Cycles ◽  
Data Set ◽  
Snow Load ◽  
Depth Data ◽  
Motion Measurements ◽  
Remote Sensing Techniques ◽  
Annual Wobble ◽  
Future Plans

A global, monthly snow depth data set has been generated from weather satellite (Nimbus 7) observations using passive microwave remote-sensing techniques. In this paper we analyzed five years of data, 1980–1984, to compute the snow-load excitation of the annual wobble of the Earth's rotation axis. A uniform sea-level decrease has been assumed in order to conserve water mass. The result shows dominant seasonal cycles. The prograde component of the annual excitation is Ψ+ = (5.0 milliarcsec, −110*) and the retrograde component Ψ− = (5.0 milliarcsec, −31*). These computed values are compared with previous groundwater estimates, as well as the inferred values from ILS and LAGEOS polar motion measurements. The importance of accurate data is stressed and future plans proposed.

scholarly journals A New Global Storage‐Area‐Depth Data Set for Modeling Reservoirs in Land Surface and Earth System Models

2018 ◽  
Vol 54 (12) ◽  
Author(s):  
Wondmagegn Yigzaw ◽  
Hong‐Yi Li ◽  
Yonas Demissie ◽  
Mohamad I. Hejazi ◽  
L. Ruby Leung ◽  
...  
Keyword(s):  
Land Surface ◽  
Earth System ◽  
Data Set ◽  
System Models ◽  
Depth Data ◽  
Storage Area ◽  
Earth System Models

scholarly journals Climatology and long-term evolution of ozone and carbon monoxide in the UTLS at northern mid-latitudes, as seen by IAGOS from 1995 to 2013

2017 ◽  
Author(s):  
Yann Cohen ◽  
Hervé Petetin ◽  
Valérie Thouret ◽  
Virginie Marécal ◽  
Béatrice Josse ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Lower Stratosphere ◽  
Boreal Summer ◽  
Brazilian Coast ◽  
Seasonal Cycles ◽  
Western Coast ◽  
Data Set ◽  
Upper Troposphere ◽  
North East ◽  
Wide Range

Abstract. In situ measurements in the upper troposphere – lower stratosphere (UTLS) are performed in the framework of the European research infrastructure IAGOS (In-service Aircraft for a Global Observing System) for ozone since 1994 and for carbon monoxide since 2002. The flight tracks cover a wide range of longitudes in the northern extratropics, extending from the North American western coast (125° W) to the eastern Asian coast (135° E), and more recently over the northern Pacific ocean. Different tropical regions are also sampled frequently, such as the Brazilian coast, central and southern Africa, southeastern Asia and the western Maritime Continent. As a result, a new set of climatologies for O3 (Aug. 1994–Dec. 2013) and CO (Dec. 2001–Dec. 2013) in the upper troposphere (UT), tropopause layer and lower stratosphere (LS) are made available, including quasi-global gridded horizontal distributions, and seasonal cycles over eight well sampled regions of interest in the northern extratropics. The seasonal cycles generally show a summertime maximum in O3 and a springtime maximum in CO in the UT, in contrast with the systematic springtime maximum in O3 and the quasi-absence of seasonal cycle of CO in the LS. This study highlights some regional variabilities in the UT notably (i) a west-east difference of O3 in boreal summer with up to 15 ppb more O3 over central Russia compared with northeast America, (ii) a systematic west-east gradient of CO from 60° E to 140° E (especially noticeable in spring and summer with about 5 ppb by 10 degrees longitude), (iii) a broad spring/summer maximum of CO over North East Asia, and (iv) a spring maximum of O3 over Western North America. Thanks to almost 20 years of O3 and 12 years of CO measurements, the IAGOS database is a unique data set to derive trends in the UTLS. Trends in O3 in the UT are positive and statistically significant in most regions, ranging from +0.25 to +0.45 ppb yr−1, characterized by the significant increase of the lowest values of the distribution. No significant trends of O3 are detected in the LS. Trends of CO in the UT, tropopause and LS are all negative and statistically significant. The estimated slopes range from −1.37 to −0.59 ppb yr−1 , with a nearly homogeneous decrease of the lowest values of the monthly distribution (fifth percentile) contrasting with the high inter-regional variability of the highest values (95th percentile).

Corrosion of Coated Pipe Samples: An Overview and Statistical Analysis of NBS-API Data

2016 ◽  
Author(s):  
Olivier Daigle ◽  
Mahesh D. Pandey
Keyword(s):  
Statistical Analysis ◽  
American Petroleum Institute ◽  
National Bureau ◽  
Data Set ◽  
Soil Corrosion ◽  
Steel Pipes ◽  
Wrought Iron ◽  
Depth Data ◽  
Pit Depth ◽  
Corrosion Of Iron

The National Bureau of Standards (NBS) had undertaken a comprehensive study of underground soil corrosion of iron pipes and plates. The maximum pit depth data for different types of wrought iron and carbon steel pipes have been widely analyzed and utilized in the corrosion literature. There is another important but relatively obscure data set about the testing of pipes with bituminous coating that NBS carried out in collaboration with the American Petroleum Institute (API). This program tested dozens of coatings on operating line pipes as well as short sections of pipes at 15 soil sites over a 10 year period (1930–1940). This paper presents an overview of this data and presents statistical analysis of protection offered by coatings.

scholarly journals Flash-Flood Susceptibility Assessment Using Multi-Criteria Decision Making and Machine Learning Supported by Remote Sensing and GIS Techniques

2019 ◽  
Vol 12 (1) ◽  
pp. 106 ◽  
Author(s):  
Romulus Costache ◽  
Quoc Bao Pham ◽  
Ehsan Sharifi ◽  
Nguyen Thi Thuy Linh ◽  
S.I. Abba ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Information Gain ◽  
Flash Flood ◽  
Slope Angle ◽  
Training Data ◽  
Operating Characteristics ◽  
Predictive Capability ◽  
Data Set ◽  
Flood Susceptibility ◽  
Remote Sensing Techniques

Concerning the significant increase in the negative effects of flash-floods worldwide, the main goal of this research is to evaluate the power of the Analytical Hierarchy Process (AHP), fi (kNN), K-Star (KS) algorithms and their ensembles in flash-flood susceptibility mapping. To train the two stand-alone models and their ensembles, for the first stage, the areas affected in the past by torrential phenomena are identified using remote sensing techniques. Approximately 70% of these areas are used as a training data set along with 10 flash-flood predictors. It should be remarked that the remote sensing techniques play a crucial role in obtaining eight out of 10 flash-flood conditioning factors. The predictive capability of predictors is evaluated through the Information Gain Ratio (IGR) method. As expected, the slope angle results in the factor with the highest predictive capability. The application of the AHP model implies the construction of ten pair-wise comparison matrices for calculating the normalized weights of each flash-flood predictor. The computed weights are used as input data in kNN–AHP and KS–AHP ensemble models for calculating the Flash-Flood Potential Index (FFPI). The FFPI also is determined through kNN and KS stand-alone models. The performance of the models is evaluated using statistical metrics (i.e., sensitivity, specificity and accuracy) while the validation of the results is done by constructing the Receiver Operating Characteristics (ROC) Curve and Area Under Curve (AUC) values and by calculating the density of torrential pixels within FFPI classes. Overall, the best performance is obtained by the kNN–AHP ensemble model.

scholarly journals Differences in mass-balance calculations resulting from alternative sampling and estimation techniques on Glacier No. 1, Tien Shan, China

1992 ◽  
Vol 16 ◽  
pp. 198-206 ◽  
Author(s):  
Kelly Elder ◽  
Richard Kattelmann ◽  
Sergei N. Ushnurtsev ◽  
Yang Daqing ◽  
Alexander Chichagov
Keyword(s):  
Soviet Union ◽  
Mass Balance ◽  
Total Mass ◽  
The United States ◽  
Accurate Estimate ◽  
Tien Shan ◽  
Cooperative Effort ◽  
Data Set ◽  
Depth Data ◽  
Intermediate Data

In May of 1990, three research groups from China, the Soviet Union and the United States visited Glacier No. 1 in the Ürümqi river basin, Xinjiang Uygur Autonomous Region, northwestern China, in a cooperative effort to examine differences in mass-balance calculations resulting from sampling and estimation procedures. Three different snow-depth data sets were collected consisting of: (1) high-resolution depth transects covering the glacier, (2) depths taken from the permanent stake network, and (3) an intermediate data set constructed using the stake network and supplementary depth data from locations not covered by the stake network. The glacier was divided into ten elevation zones and the data were registered to a digital elevation model for analysis. Results show that the permanent stake network provides an accurate estimate of total mass balance if certain techniques are used for extrapolation to higher elevations, although estimates of mass balance for particular regions of the glacier are not accurate. Some regions were overestimated while others were underestimated, leading to a good overall estimate. The intermediate-resolution data set provided better within-zone estimates of mass balance, but was less accurate than the stake network for total mass balance.

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