scholarly journals A new global gridded glacier dataset based on the Randolph Glacier Inventory version 6.0

2021 ◽  
pp. 1-4
Author(s):  
Yaojun Li ◽  
Fei Li ◽  
Donghui Shangguan ◽  
Yongjian Ding
Keyword(s):  
Meteorological Variables ◽  
Gridded Data ◽  
Glacier Inventory ◽  
Gridded Dataset ◽  
Good Consistency ◽  
Good Agreement

Abstract Gridded glacier datasets are essential for various glaciological and climatological research because they link glacier cover with the corresponding gridded meteorological variables. However, there are significant differences between the gridded data and the shapefile data in the total area calculations in the Randolph Glacier Inventory (RGI) 6.0 at global and regional scales. Here, we present a new global gridded glacier dataset based on the RGI 6.0 that eliminates the differences. The dataset is made by dividing the glacier polygons using cell boundaries and then recalculating the area of each polygon in the cell. Our dataset (1) exhibits a good agreement with the RGI area values for those regions in which gridded areas showed a generally good consistency with those in the shapefile data, and (2) reduces the errors existing in the current RGI gridded dataset. All data and code used in this study are freely available and we provide two examples to demonstrate the application of this new gridded dataset.

scholarly journals Estimate of Glacier Ablation under a Debris Layer from Surface Temperature and Meteorological Variables

1982 ◽  
Vol 28 (98) ◽  
pp. 29-34 ◽  
Author(s):  
M. Nakawo ◽  
G.J. Young
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Surface Temperature ◽  
Temperature Data ◽  
Meteorological Variables ◽  
Glacier Ablation ◽  
Surface Temperature Data ◽  
Good Agreement

AbstractA simple model suggests that the ablation under a debris layer could be estimated from meteorological variables if the surface temperature data of the layer are available. This method was tested by analyzing the data obtained from experiments with artificial debris layers. Fairly good agreement was obtained between the estimated and the experimental data.

scholarly journals Repeatability of the Universiti Teknologi MARA reading charts

2015 ◽  
Vol 14 (3) ◽  
pp. 236-240 ◽  
Author(s):  
Noor Halilah Buari ◽  
Nur Hidayah Yusuf ◽  
Adib Mohd Satali ◽  
Ai Hong Chen
Keyword(s):  
Random Sequence ◽  
Medical Science ◽  
Reading Rate ◽  
Read Aloud ◽  
Intra Class Correlation ◽  
Significant Difference ◽  
Good Consistency ◽  
Reading Charts ◽  
Intra Class Correlation Coefficient ◽  
Good Agreement

Objective: This study was done to investigate the repeatability measurements in reading rate using the Universiti Teknologi MARA Malay related words (UiTM-Mrw) reading chart and Universiti Teknologi MARA Malay unrelated words (UiTM-Muw) reading chart. Methodology: Thirty normally sighted participants were randomly recruited through randomised sampling (mean age =21.5±1.1 years). Participants were instructed to read aloud, clearly and as quickly as possible at 2 different sessions using two different charts. The two charts were selected at random sequence. A minimum of 7 days interval was used to minimize the learning affect. The time taken to read each chart was recorded and any errors while reading was noted. Reading performance was quantified as reading rate in words per minute (wpm). Results: Comparison of reading rate between session 1 and session 2 was not significantly different (p=0.894, df=1, F=0.018) for UiTM-Mrw reading chart. The reading rate between session 1 and 2 also showed no significant difference (p=0.99, df=1, F=2.811) in UiTM-Muw reading chart. Intra-class correlation coefficient (ICC) showed a good consistency in repeatability for both UiTM-Mrw reading chart and UiTM-Muw reading chart with ICC values of 0.849 and 0.814 respectively. The Bland and Altman plot between measurement of reading rate in session 1 and session 2 showed a good agreement in UiTM-Mrw reading chart and UiTM-Muw reading chart. Conclusion: Both UiTM-Mrw reading chart and UiTM-Mur reading chart showed a good consistency and good agreement in repeated measurement of reading rate.Bangladesh Journal of Medical Science Vol.14(3) 2015 p.236-240

scholarly journals An improved transmitter system to accurately measure wet-bulb temperature of air

2019 ◽  
Vol 52 (7-8) ◽  
pp. 1002-1007
Author(s):  
Liangwen Yan ◽  
Peng Yu ◽  
Sijung Hu ◽  
Qiu Gao ◽  
Wei Li ◽  
...  
Keyword(s):  
Real Time ◽  
Latent Heat ◽  
Measurement Accuracy ◽  
Cost Effective ◽  
Mean Value ◽  
Experimental Results ◽  
Iteration Algorithm ◽  
Good Consistency ◽  
The Mean ◽  
Good Agreement

A cost-effective measurement of wet-bulb temperature of air has great benefits to fulfill a growing demand of industry, cultivation agriculture, and medication. Applying an appropriate algorithm to wet-bulb temperature of air measurement can effectively improve the accuracy and speed of its measurement. The study aims to research how an improved transmitter system along with the latent heat–based iteration algorithm is used to precisely measure wet-bulb temperature of air. The work consists of (1) simulation of the iteration algorithm and (2) validation via experimental protocol. The simulation results through latent heat–based iteration algorithm were in good agreement ( R2≥ 0.99) with the reference. The performance of the improved wet-bulb temperature of air transmitter system was tested by a latent heat–based iteration algorithm experimental setup. The experimental results demonstrate that the improved wet-bulb temperature of air in a good consistency with commercial wet-bulb temperature of air in a range of temperature (15°C–34°C) and relative humidity (28.8%–76.2%). The Bland–Altman plot also shows that the mean value and the standard deviation of the differences between these two systems are 0.14°C and 0.29°C, respectively, which indicates that the improved wet-bulb temperature of air has a good agreement as well. Compared with the commercial wet-bulb temperature of air transmitter system, an advanced processor (STM32F103C8T6) and real-time operating system was applied in the improved wet-bulb temperature of air transmitter system. The experimental results show that its measurement accuracy is closer to the previous study. This study provides an alternative and cost-effective solution to accurately and real-time measure wet-bulb temperature of air.

Theoretical photoionization study of Ti9+ ion

2020 ◽  
Author(s):  
Hongbin Wang ◽  
Gang Jiang
Keyword(s):  
Cross Sections ◽  
Energy Levels ◽  
Radiative Transition ◽  
High Energy ◽  
Low Energy ◽  
Transition Rates ◽  
Channel Coupling ◽  
R Matrix ◽  
Good Consistency ◽  
Good Agreement

Photoionization (PI) of Ti<sup>9+</sup> ion is investigated by the Dirac R-matrix method. Multi-Configuration Dirac-Fock (MCDF) calculations are performed to construct accurate target functions. Good agreement of energy levels and radiative transition rates indicate the accuracy of target functions. PI cross sections show good consistency between length and velocity forms. The results are consistent with the previous theoretical values in high-energy regions. Partial waves contribution to the total PI cross sections are discussed for the ground and metastable states. Moreover, the PI cross sections are dominated by many resonance structures and affected by the channel coupling effects in low-energy region. In addition to providing data for the Opacity Project TOPbase, the present work promotes plasma simulation and diagnosis.

scholarly journals A new glacier inventory for the Jostedalsbreen region, Norway, from Landsat TM scenes of 2006 and changes since 1966

2011 ◽  
Vol 52 (59) ◽  
pp. 153-162 ◽  
Author(s):  
Frank Paul ◽  
Liss M. Andreassen ◽  
Solveig H. Winsvold
Keyword(s):  
Field Measurements ◽  
Glacier Inventory ◽  
Digital Elevation ◽  
Cumulative Length ◽  
Length Changes ◽  
Snow Conditions ◽  
The 1960S ◽  
Elevation Model ◽  
Good Agreement ◽  
Area Determination

AbstractPronounced changes in glacier mass and length were observed for the monitored glaciers in the Jostedalsbreen region, Norway, since the last glacier inventories were compiled in the 1960s and 1980s. However, the current overall extent of the glaciers in the region is not well known. To obtain this information, we have compiled a new inventory from two mosaicked Landsat Thematic Mapper (TM) scenes acquired in 2006 that have excellent snow conditions for glacier mapping, the first suitable scenes for this purpose after 22 years of imaging with TM. Drainage divides and topographic inventory parameters were derived from a 25 m national digital elevation model for 1450 glaciers. By digitizing glacier outlines from 1 : 50 000 scale topographic maps of 1966, we calculated changes in glacier area for ~300 glaciers. Cumulative length changes for the 1997–2006 period were derived from an additional TM scene and compared with field measurements for nine glaciers. Overall, we find a 9% area loss since 1966, with a clear dependence on glacier size; however, seasonal snow in 1966 in some regions made area determination challenging. The satellite-derived length changes confirmed the observed high spatial variability and were in good agreement with field data (±1 pixel), apart from glacier tongues in cast shadow. The new inventory will be freely available from the Global Land Ice Measurements from Space (GLIMS) glacier database.

scholarly journals Estimate of Glacier Ablation under a Debris Layer from Surface Temperature and Meteorological Variables

1982 ◽  
Vol 28 (98) ◽  
pp. 29-34 ◽  
Author(s):  
M. Nakawo ◽  
G.J. Young
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Surface Temperature ◽  
Temperature Data ◽  
Meteorological Variables ◽  
Glacier Ablation ◽  
Surface Temperature Data ◽  
Good Agreement

AbstractA simple model suggests that the ablation under a debris layer could be estimated from meteorological variables if the surface temperature data of the layer are available. This method was tested by analyzing the data obtained from experiments with artificial debris layers. Fairly good agreement was obtained between the estimated and the experimental data.

scholarly journals Automatic Lidar Calibration and Processing Program for Multiwavelength Raman Polarization Lidar

2020 ◽  
Vol 237 ◽  
pp. 08007
Author(s):  
Zhenping Yin ◽  
Holger Baars ◽  
Patric Seifert ◽  
Ronny Engelmann
Keyword(s):  
Water Vapor ◽  
Mixing Ratio ◽  
Extinction Coefficients ◽  
Good Consistency ◽  
Processing Program ◽  
Lidar Ratio ◽  
Water Vapor Mixing Ratio ◽  
Lidar Calibration ◽  
Aerosol Backscatter ◽  
Good Agreement

A new version of automatic lidar calibration and processing program was developed to process the data from multiwavelength Raman polarization lidar. The absolute lidar calibration and water vapor calibration algorithms were applied. The program can provide plentiful products, like aerosol backscatter and extinction coefficients, lidar ratio, Ångström exponent, volume and particle depolarization ratios, water vapor mixing ratio and aerosol target classification. Good agreement was found in the comparison with manual quality-assured profiles or radiosonde measurement. Lidar calibration based on the aerosol optical properties retrieved with Raman method, Klett method and AOD-Constrained method were implemented. Good consistency was found.

scholarly journals Soil moisture active and passive microwave products: intercomparison and evaluation over a Sahelian site

2009 ◽  
Vol 6 (4) ◽  
pp. 5303-5339 ◽  
Author(s):  
C. Gruhier ◽  
P. de Rosnay ◽  
S. Hasenauer ◽  
T. Holmes ◽  
R. de Jeu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Temporal Variations ◽  
Signal Frequency ◽  
Convective Rainfall ◽  
Ground Station ◽  
Multidisciplinary Analysis ◽  
Good Consistency ◽  
Rainfall Occurrences ◽  
Meso Scale ◽  
Good Agreement

Abstract. This paper presents a comparison and an evaluation of five soil moisture products based on satellite-based passive and active microwave measurements. Products are evaluated for 2005–2006 against ground measurements obtained from the soil moisture network deployed in Mali (Sahel) in the framework of the African Monsoon Multidisciplinary Analysis project. It is shown that the accuracy of the soil moisture products is sensitive to the retrieval approach as well as to the sensor type (active or passive) and to the signal frequency (from 5.6 GHz to 18.8 GHz). The spatial patterns of surface soil moisture are compared between the different products at meso-scale (14.5° N–17.5° N and 2° W–1° W). A general good consistency between the different satellite soil moisture products is shown in terms of meso-scale spatial distribution, in particular after convective rainfall occurrences. Soil moisture values provided by the different products are compared to ground measurements time series. Although soil moisture products obtained from satellite generally over-estimate soil moisture values during the dry season, most of them capture soil moisture temporal variations in good agreement with ground station measurements.

scholarly journals Soil moisture active and passive microwave products: intercomparison and evaluation over a Sahelian site

2010 ◽  
Vol 14 (1) ◽  
pp. 141-156 ◽  
Author(s):  
C. Gruhier ◽  
P. de Rosnay ◽  
S. Hasenauer ◽  
T. Holmes ◽  
R. de Jeu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Temporal Variations ◽  
Signal Frequency ◽  
Ground Station ◽  
Multidisciplinary Analysis ◽  
Ground Measurement ◽  
Good Consistency ◽  
Rainfall Occurrences ◽  
Meso Scale ◽  
Good Agreement

Abstract. This paper presents a comparison and an evaluation of five soil moisture products based on satellite-based passive and active microwave measurements. Products are evaluated for 2005–2006 against ground measurements obtained from the soil moisture network deployed in Mali (Sahel) in the framework of the African Monsoon Multidisciplinary Analysis project. It is shown that the accuracy of the soil moisture products is sensitive to the retrieval approach as well as to the sensor type (active or passive) and to the signal frequency (from 5.6 GHz to 18.8 GHz). The spatial patterns of surface soil moisture are compared between the different products at meso-scale (14.5° N–17.5° N and 2° W–1° W). A general good consistency between the different satellite soil moisture products is shown in terms of meso-scale spatial distribution, in particular after convective rainfall occurrences. Comparison to ground measurement shows that although soil moisture products obtained from satellite generally over-estimate soil moisture values during the dry season, most of them capture soil moisture temporal variations in good agreement with ground station measurements.

scholarly journals Derivation and analysis of a complete modern-date glacier inventory for Alaska and northwest Canada

2015 ◽  
Vol 61 (227) ◽  
pp. 403-420 ◽  
Author(s):  
Christian Kienholz ◽  
Sam Herreid ◽  
Justin L. Rich ◽  
Anthony A. Arendt ◽  
Regine Hock ◽  
...  
Keyword(s):  
Preliminary Analysis ◽  
Ice Sheets ◽  
Systematic Errors ◽  
Alaska Range ◽  
Glacier Inventory ◽  
Debris Cover ◽  
Scaling Parameters ◽  
Length Scaling ◽  
Different Sources ◽  
Good Agreement

AbstractWe present a detailed, complete glacier inventory for Alaska and neighboring Canada using multi-sensor satellite data from 2000 to 2011. For each glacier, we derive outlines and 51 variables, including center-line lengths, outline types and debris cover. We find 86 723 km2of glacier area (27 109 glaciers >0.025 km2), ∼12% of the global glacierized area outside ice sheets. Of this area 12.0% is drained by 39 marine-terminating glaciers (74 km of tidewater margin), and 19.3% by 148 lake- and river-terminating glaciers (420 km of lake-/river margin). The overall debris cover is 11%, with considerable differences among regions, ranging from 1.4% in the Kenai Mountains to 28% in the Central Alaska Range. Comparison of outlines from different sources on >2500 km2of glacierized area yields a total area difference of ∼10%, emphasizing the difficulties in accurately delineating debris-covered glaciers. Assuming fully correlated (systematic) errors, uncertainties in area reach 6% for all Alaska glaciers, but further analysis is needed to explore adequate error correlation scales. Preliminary analysis of the glacier database yields a new set of well-constrained area/length scaling parameters and shows good agreement between our area–altitude distributions and previously established synthetic hypsometries. The new glacier database will be valuable to further explore relations between glacier variables and glacier behavior.

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