Testing and Development of Transfer Functions for Weighing Precipitation Gauges in WMO-SPICE

Abstract. Adjustments for the undercatch of solid precipitation caused by wind were developed for different weighing gauge/wind shield combinations tested in WMO-SPICE. These include several different manufacturer-provided unshielded and single-Alter shielded weighing gauges, a MRW500 precipitation gauge within a small, manufacturer-provided shield, and host-provided precipitation gauges within double-Alter, Belfort double-Alter, and small Double-Fence Intercomparison Reference (SDFIR) shields. Previously-derived adjustments were also tested on measurements from each weighing gauge/wind shield combination. The transfer functions developed specifically for each of the different types of unshielded and single-Alter shielded weighing gauges did not perform significantly better than the more generic and universal transfer functions developed previously using measurements from eight different WMO-SPICE sites. This indicates that wind shield type (or lack thereof) is more important in determining the magnitude of wind-induced undercatch than the type of weighing precipitation gauge. It also demonstrates the potential for widespread use of the previously-developed, multi-site single-Alter shielded and unshielded transfer functions. In addition, corrections for the lower-porosity Belfort double-Alter shield and a standard double-Alter shield were developed and tested using measurements from two separate sites for the first time. Among all of the manufacturer-provided shields tested, with an average undercatch of about 5 %, the Belfort double Alter shield required the least amount of correction, and caught ~ 80 % of the reference amount of precipitation even in snowy conditions with wind speeds greater than 5 m s−1. The SDFIR-shielded gauge accumulated 98 % of the Double-Fence Automated Reference (DFAR) precipitation amount on average, accumulated 90 % of the DFAR accumulation in high winds, and was almost indistinguishable from the full-sized DFAR used as a reference. In general, the more effective wind shields, that were associated with smaller unadjusted errors, also produced more accurate measurements after adjustment.

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Assessment of snowfall accumulation underestimation by tipping bucket gauges in the Spanish operational network

Atmospheric Measurement Techniques ◽

10.5194/amt-10-1079-2017 ◽

2017 ◽

Vol 10 (3) ◽

pp. 1079-1091 ◽

Cited By ~ 16

Author(s):

Samuel T. Buisán ◽

Michael E. Earle ◽

José Luís Collado ◽

John Kochendorfer ◽

Javier Alastrué ◽

...

Keyword(s):

Transfer Functions ◽

Test Site ◽

Environmental Variable ◽

State Agency ◽

Mountain Range ◽

Northern Spain ◽

Wind Speeds ◽

Solid Precipitation ◽

The World ◽

Precipitation Gauge

Abstract. Within the framework of the World Meteorological Organization Solid Precipitation Intercomparison Experiment (WMO-SPICE), the Thies tipping bucket precipitation gauge was assessed against the SPICE reference configuration at the Formigal–Sarrios test site located in the Pyrenees mountain range of Spain. The Thies gauge is the most widely used precipitation gauge by the Spanish Meteorological State Agency (AEMET) for the measurement of all precipitation types including snow. It is therefore critical that its performance is characterized. The first objective of this study is to derive transfer functions based on the relationships between catch ratio and wind speed and temperature. Multiple linear regression was applied to 1 and 3 h accumulation periods, confirming that wind is the most dominant environmental variable affecting the gauge catch efficiency, especially during snowfall events. At wind speeds of 1.5 m s−1 the tipping bucket recorded only 70 % of the reference precipitation. At 3 m s−1, the amount of measured precipitation decreased to 50 % of the reference, was even lower for temperatures colder than −2 °C and decreased to 20 % or less for higher wind speeds.The implications of precipitation underestimation for areas in northern Spain are discussed within the context of the present analysis, by applying the transfer function developed at the Formigal–Sarrios and using results from previous studies.

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Estimation of Wind-Induced Losses from a Precipitation Gauge Network in the Australian Snowy Mountains

Journal of Hydrometeorology ◽

10.1175/jhm-d-14-0216.1 ◽

2015 ◽

Vol 16 (6) ◽

pp. 2619-2638 ◽

Cited By ~ 16

Author(s):

Thomas Chubb ◽

Michael J. Manton ◽

Steven T. Siems ◽

Andrew D. Peace ◽

Shane P. Bilish

Keyword(s):

Ambient Temperature ◽

Precipitation Amount ◽

Case Scenario ◽

Worst Case ◽

Alpine Environment ◽

Substantial Impact ◽

Precipitation Gauge ◽

High Winds ◽

Alpine Environments ◽

Adjustment Scheme

Abstract Wind-induced losses, or undercatch, can have a substantial impact on precipitation gauge observations, especially in alpine environments that receive a substantial amount of frozen precipitation and may be exposed to high winds. A network of NOAH II all-weather gauges installed in the Snowy Mountains since 2006 provides an opportunity to evaluate the magnitude of undercatch in an Australian alpine environment. Data from two intercomparison sites were used with NOAH II gauges with different configurations of wind fences installed: unfenced, WMO standard double fence intercomparison reference (full DFIR) fences, and an experimental half-sized double fence (half DFIR). It was found that average ambient temperature over 6-h periods was sufficient to classify the precipitation phase as snow, mixed precipitation, or rain in a statistically robust way. Empirical catch ratio relationships (i.e., the quotient of observations from two gauges), based on wind speed, ambient temperature, and measured precipitation amount, were established for snow and mixed precipitation. An adjustment scheme to correct the unfenced NOAH II gauge data using the catch ratio relationships was cross validated with independent data from two additional sites, as well as from the intercomparison sites themselves. The adjustment scheme was applied to the observed precipitation amounts at the other sites with unfenced NOAH II gauges. In the worst-case scenario, it was found that the observed precipitation amount would need to be increased by 52% to match what would have been recorded had adequate shielding been installed. However, gauges that were naturally well protected, and those below about 1400 m, required very little adjustment. Spatial analysis showed that the average seasonal undercatch was between 6% and 15% for gauges above 1000 m MSL.

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Improvement of solid precipitation measurements using a hotplate precipitation gauge

Journal of Hydrometeorology ◽

10.1175/jhm-d-20-0168.1 ◽

2021 ◽

Author(s):

Julie M. Thériault ◽

Nicolas R. Leroux ◽

Roy Rasmussen

Keyword(s):

Wind Speed ◽

Transfer Functions ◽

Collection Efficiency ◽

Meteorological Conditions ◽

Speed Limit ◽

Mean Square ◽

Wind Speeds ◽

Solid Precipitation ◽

Precipitation Measurement ◽

Precipitation Gauge

AbstractAccurate snowfall measurement is challenging because it depends on the precipitation gauge used, meteorological conditions, and the precipitation microphysics. Upstream of weighing gauges, the flow field is disturbed by the gauge and any shielding used usually creates an updraft, which deflects solid precipitation from falling in the gauge resulting in significant undercatch. Wind shields are often used with weighing gauges to reduce this updraft and transfer functions are required to adjust the snowfall measurements to consider gauge undercatch. Using these functions reduce the bias in precipitation measurement but not the Root Mean Square Error (RMSE) (Kochendorfer et al. 2017a, b). The analysis performed in this study shows that the hotplate precipitation gauge bias after wind correction is near zero and similar to wind corrected weighing gauges but improves on the RMSE or scatter of the collection efficiency of weighing gauges for a given wind speed. To do this, the accuracy of the hotplate was compared to standard unshielded and shielded weighing gauges collected during the WMO SPICE program. The RMSE of the hotplate measurements is lower than weighing gauges (with or without an Alter shield) for wind speeds up to 5 m s-1; the wind speed limit at which sufficient data were available. This study shows that the hotplate precipitation measurement has a low bias and RMSE due to its aerodynamic shape, making its performance mostly independent of the type of solid precipitation.

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The quantification and correction of wind-induced precipitation measurement errors

Hydrology and Earth System Sciences ◽

10.5194/hess-21-1973-2017 ◽

2017 ◽

Vol 21 (4) ◽

pp. 1973-1989 ◽

Cited By ~ 48

Author(s):

John Kochendorfer ◽

Roy Rasmussen ◽

Mareile Wolff ◽

Bruce Baker ◽

Mark E. Hall ◽

...

Keyword(s):

Measurement Errors ◽

Transfer Functions ◽

Climate Change Research ◽

Wind Speeds ◽

Solid Precipitation ◽

Precipitation Measurement ◽

Single Function ◽

Safety Work ◽

The Usa ◽

Precipitation Gauge

Abstract. Hydrologic measurements are important for both the short- and long-term management of water resources. Of the terms in the hydrologic budget, precipitation is typically the most important input; however, measurements of precipitation are subject to large errors and biases. For example, an all-weather unshielded weighing precipitation gauge can collect less than 50 % of the actual amount of solid precipitation when wind speeds exceed 5 m s−1. Using results from two different precipitation test beds, such errors have been assessed for unshielded weighing gauges and for weighing gauges employing four of the most common windshields currently in use. Functions to correct wind-induced undercatch were developed and tested. In addition, corrections for the single-Alter weighing gauge were developed using the combined results of two separate sites in Norway and the USA. In general, the results indicate that the functions effectively correct the undercatch bias that affects such precipitation measurements. In addition, a single function developed for the single-Alter gauges effectively decreased the bias at both sites, with the bias at the US site improving from −12 to 0 %, and the bias at the Norwegian site improving from −27 to −4 %. These correction functions require only wind speed and air temperature as inputs, and were developed for use in national and local precipitation networks, hydrological monitoring, roadway and airport safety work, and climate change research. The techniques used to develop and test these transfer functions at more than one site can also be used for other more comprehensive studies, such as the World Meteorological Organization Solid Precipitation Intercomparison Experiment (WMO-SPICE).

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The Quantification and Correction of Wind-Induced Precipitation Measurement Errors

10.5194/hess-2016-415 ◽

2016 ◽

Author(s):

John Kochendorfer ◽

Roy Rasmussen ◽

Mareile Wolff ◽

Bruce Baker ◽

Mark E. Hall ◽

...

Keyword(s):

Wind Speed ◽

Air Temperature ◽

Measurement Errors ◽

Transfer Functions ◽

Universal Function ◽

Climate Change Research ◽

Wind Speeds ◽

Solid Precipitation ◽

The Us ◽

Precipitation Gauge

Abstract. Hydrologic measurements are becoming increasingly important for both the short and long term management of water resources. Of all the terms in the hydrologic budget, precipitation is the typically most important input. However, measurements of precipitation are still subject to large errors and biases. For example, a high-quality but unshielded weighing precipitation gauge can collect less than 50 % of the actual amount of solid precipitation when wind speeds exceed 5 ms−1. Using results from two different precipitation testbeds, such errors have been assessed for unshielded weighing gauges and for four of the most common windshields currently in use. Functions used to correct wind-induced undercatch were developed and tested. In addition, corrections for the single Altar weighing gauge were developed using the combined results of two separate sites, one of which was in Norway and other in the US. In general the results indicate that corrections described as a function of air temperature and wind speed effectively remove the undercatch bias that affects such precipitation measurements. In addition, a single ‘universal’ function developed for the single Altar gauges effectively removed the bias at both sites, with the bias at the US site improved from −12 % to 0 %, and the bias at the Norwegian site improved from −27 % to −3 %. These correction functions require only wind speed and air temperature, and were developed for use in national and local precipitation networks, hydrological monitoring, roadway and airport safety work, and climate change research. The techniques used to develop and test these transfer functions at more than one site can also be used for other more comprehensive studies, such as the WMO Solid Precipitation Intercomparison Experiment.

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Intercomparison of Solid Precipitation Derived from the Weighting Rain Gauge and Optical Instruments in the Interior Qinghai-Tibetan Plateau

Advances in Meteorology ◽

10.1155/2015/936724 ◽

2015 ◽

Vol 2015 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Lele Zhang ◽

Lin Zhao ◽

Changwei Xie ◽

Guangyue Liu ◽

Liming Gao ◽

...

Keyword(s):

Tibetan Plateau ◽

Precipitation Amount ◽

Cold Season ◽

Rain Gauge ◽

Strong Wind ◽

Wind Speeds ◽

Optical Instruments ◽

Solid Precipitation ◽

Precipitation Gauge ◽

Light Precipitation

Due to the light precipitation and strong wind in the cold season, it is hard to get credible solid precipitation on the Qinghai-Tibetan plateau (QTP). To address this issue, two kinds of optical instruments, the Thies Laser Precipitation Monitor (LPM) and OTT laser-optical Particle Size Velocity (Parsivel), were used on QTP. The measured precipitation was compared with the precipitation derived from Geonor T-200B precipitation gauge (Geonor). The results showed that Geonor was hard to catch light precipitation (precipitation amount was less than 1 mm during a single event) when the wind speeds were higher than 3.5 m/s. Even when the wind speeds were smaller than 3.5 m/s, about 44% of such light precipitation events were not recorded by Geonor. The optical instruments had much better performance in recording light precipitation. Three methods were used to correct Geonor measurements of daily solid precipitation and the corrected values were set as reference for assessing the performance of LPM and Parsivel; the results showed that LPM had good performance in measuring the solid precipitation but Parsivel overestimated the precipitation amount. Methods for correcting Geonor’s hourly solid precipitation and recalculating Parsivel’s solid precipitation amount were also proposed in this paper.

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Assessment of the underestimation of snowfall accumulation by tipping bucket gauges used operationally by the Spanish national weather service

10.5194/amt-2016-197 ◽

2016 ◽

Cited By ~ 1

Author(s):

Samuel T. Buisan ◽

Michael E. Earle ◽

José Luís Collado ◽

John Kochendorfer ◽

Javier Alastrué ◽

...

Keyword(s):

Transfer Functions ◽

Weather Conditions ◽

Test Site ◽

Environmental Variable ◽

State Agency ◽

Mountain Range ◽

Northern Spain ◽

Wind Speeds ◽

Precipitation Gauge ◽

Average Catch

Abstract. Within the framework of the WMO-SPICE (Solid Precipitation Intercomparison Experiment) at the Formigal-Sarrios test site located in the Pyrenees mountain range of Spain, the Thies tipping bucket precipitation gauge was assessed against the SPICE reference. The Thies gauge is the most widely-used precipitation gauge by the Spanish Meteorological State Agency (AEMET) for the measurement of all precipitation types, including snow. It is therefore critical that its performance be characterized. The first objective of this study is to derive transfer functions based on the relationships between catch ratio and wind speed and temperature. Multiple linear regression was applied to 1 h and 3 h accumulation periods, confirming that wind is the most dominant environmental variable affecting the gauge catch efficiency, especially during snowfall events. At wind speeds of 1.5 m s−1 the average catch ratio was 0.7. At 3 m s−1, the average catch ratio was 0.5, and was even lower for temperatures below −2 ºC and decreased to 0.2 or less for higher wind speeds. Following this, this study outlines two areas in Northern Spain that exhibit different catch ratios under weather conditions leading to snowfall events, highlighting the importance of how the precipitation gauge behaves in various conditions.

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Effect of Antibacterial Root Canal Sealer on Persistent Apical Periodontitis

Antibiotics ◽

10.3390/antibiotics10060741 ◽

2021 ◽

Vol 10 (6) ◽

pp. 741

Author(s):

Zheng Wang ◽

Ge Yang ◽

Biao Ren ◽

Yuan Gao ◽

Xian Peng ◽

...

Keyword(s):

Enterococcus Faecalis ◽

Therapeutic Effect ◽

Root Canal ◽

Apical Periodontitis ◽

Control Group ◽

Root Canal Sealer ◽

Root Canal Filling ◽

First Time ◽

Cone Beam Computer Tomography ◽

Better Than

The infection of Enterococcus faecalis and its interacting microorganisms in the root canal could cause persistent apical periodontitis (AP). Antibacterial root canal sealer has favorable prospects to inhibit biofilms. The purpose of this study was to investigated the antibacterial effect of root canal sealer containing dimethylaminododecyl methacrylate (DMADDM) on persistent AP in beagle dogs for the first time. Persistent AP was established by a two-step infection with Enterococcus faecalis and multi-bacteria (Enterococcus faecalis, Lactobacillus acidophilus, Actinomycesnaeslundii, Streptococcus gordonii). Root canal sealer containing DMADDM (0%, 1.25%, 2.5%) was used to complete root canal filling. The volume of lesions and inflammatory grade in the apical area were evaluated by cone beam computer tomography (CBCT) and hematoxylin-eosin staining. Both Enterococcus-faecalis- and multi-bacteria-induced persistent AP caused severe apical destruction, and there were no significant differences in pathogenicity between them. DMADDM-modified sealer significantly reduced the volume of periapical lesion and inflammatory grade compared with the control group, among them, the therapeutic effect of the 2.5% group was better than the 1.25% group. In addition, E.faecalis-induced reinfection was more sensitive to the 2.5% group than multi-bacteria reinfection. This study shows that root canal sealer containing DMADDM had a remarkable therapeutic effect on persistent AP, especially on E. faecalis-induced reinfection.

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CPC2 Reduction with Hipparcos and Proper Motions in The Southern Hemisphere

Highlights of Astronomy ◽

10.1017/s153929960002205x ◽

1998 ◽

Vol 11 (1) ◽

pp. 551-551

Author(s):

N. Zacharias ◽

M.I. Zacharias ◽

C. de Vegt ◽

C.A. Murray

Keyword(s):

Southern Hemisphere ◽

Systematic Errors ◽

Reference Star ◽

Proper Motions ◽

Positional Accuracy ◽

Star Catalog ◽

Naval Observatory ◽

Celestial Reference System ◽

First Time ◽

Better Than

The Second Cape Photographic Catalog (CPC2) contains 276,131 stars covering the entire Southern Hemisphere in a 4-fold overlap pattern. Its mean epoch is 1968, which makes it a key catalog for proper motions. A new reduction of the 5687 plates using on average 40 Hipparcos stars per plate has resulted in a vastly improved catalog with a positional accuracy of about 40 mas (median value) per coordinate, which comes very close to the measuring precision. In particular, for the first time systematic errors depending on magnitude and color can be solved unambiguously and have been removed from the catalog. In combination with the Tycho Catalogue (mean epoch 1991.25) and the upcoming U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project proper motions better than 2 mas/yr can be obtained. This will lead to a vastly improved reference star catalog in the Southern Hemisphere for the final Astrographic Catalogue (AC) reductions, which will then provide propermotions for millions of stars when combined with new epoch data. These data then will allow an uncompromised reduction of the southern Schmidt surveys on the International Celestial Reference System (ICRS).

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Investigation of Solubility Behavior of Canagliflozin Hydrate Crystals Combining Crystallographic and Hirshfeld Surface Calculations

Molecules ◽

10.3390/molecules26020298 ◽

2021 ◽

Vol 26 (2) ◽

pp. 298

Author(s):

Yefen Zhu ◽

Yanlei Kang ◽

Ling Zhu ◽

Kaxi Yu ◽

Shuai Chen ◽

...

Keyword(s):

Crystal Structure ◽

Intermolecular Forces ◽

Hirshfeld Surface ◽

Reversible Inhibitor ◽

Solubility Behavior ◽

Hydrogen Bond Networks ◽

Solvent Molecules ◽

First Time ◽

Better Than

Canagliflozin (CG) was a highly effective, selective and reversible inhibitor of sodium-dependent glucose co-transporter 2 developed for the treatment of type 2 diabetes mellitus. The crystal structure of CG monohydrate (CG-H2O) was reported for the first time while CG hemihydrate (CG-Hemi) had been reported in our previous research. Solubility and dissolution rate results showed that the solubility of CG-Hemi was 1.4 times higher than that of CG-H2O in water and hydrochloric acid solution, and the dissolution rates of CG-Hemi were more than 3 folds than CG-H2O in both solutions. Hirshfeld surface analysis showed that CG-H2O had stronger intermolecular forces than CG-Hemi, and water molecules in CG-H2O participated three hydrogen bonds, forming hydrogen bond networks. These crystal structure features might make it more difficult for solvent molecules to dissolve CG-H2O than CG-Hemi. All these analyses might explain why the dissolution performance of CG-Hemi was better than CG-H2O. This work provided an approach to predict the dissolution performance of the drug based on its crystal structure.

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