scholarly journals Naturally triggered persistent deep slab avalanches in western Canada Part I: avalanche characteristics and weather trends from weather stations

2016 ◽  
Vol 62 (232) ◽  
pp. 243-255 ◽  
Author(s):  
MICHAEL CONLAN ◽  
BRUCE JAMIESON
Keyword(s):  
Air Temperature ◽  
Classification Tree ◽  
Decision Aids ◽  
Companion Paper ◽  
Wind Loading ◽  
False Alarms ◽  
Western Canada ◽  
Weather Model ◽  
Weather Stations ◽  
Median Maximum

ABSTRACTA database of difficult-to-forecast natural persistent deep slab avalanches was analyzed to determine thresholds for parameters that contribute to their release in western Canada. The database included avalanche observations and weather station data. The avalanches were grouped based on their primary cause-of-release, either precipitation loading, wind loading, solar warming or air temperature warming using a multivariate classification tree, which first split using a solar warming parameter. The precipitation group had a median 24 h snowfall of 15 cm and 3 d snowfall of 38 cm at weather stations, mostly at or below treeline. These amounts were likely closer between 20–30 and 50–80 cm at alpine start zones. The wind loading group experienced the most wind-transported snow potential. The solar warming group had predicted solar warming of 5.2°C, 10 cm into the snowpack, on the days of release. The air temperature warming group experienced the highest median maximum air temperature (5°C) on the days of release. These thresholds may be useful to forecast the likelihood of similar avalanches with experienced-based forecasting or with decision aids, although many false alarms are possible. A companion paper, Part II, relates weather model data to avalanche occurrences.

scholarly journals Naturally triggered persistent deep slab avalanches in western Canada Part II: weather trends from model forecasts

2016 ◽  
Vol 62 (232) ◽  
pp. 256-269 ◽  
Author(s):  
MICHAEL CONLAN ◽  
BRUCE JAMIESON
Keyword(s):  
Classification Tree ◽  
Surface Wind ◽  
Critical Parameters ◽  
Wind Loading ◽  
Weather Data ◽  
Limited Area ◽  
Weather Station ◽  
Station Data ◽  
Weather Station Data ◽  
Weather Stations

ABSTRACTFor 175 difficult-to-forecast persistent deep slab avalanches, weather data were obtained from Global Environmental Multiscale (GEM) models produced by Environment Canada. The focus was to determine critical parameters and thresholds for avalanche forecasting from GEM and compare them with weather station data analyzed in Part I (Conlan and Jamieson, this issue). The high-resolution GEM-limited-area model (2.5 km resolution) forecasted higher median precipitation amounts than both the lower-resolution GEM15 (15 km resolution) and weather stations within a small dataset. Air temperatures were lower for both weather models compared with the weather station data, likely because of elevation differences. A multivariate classification tree created with GEM15 data correctly classified 29 of 36 avalanches by their primary cause-of-release, using a primary split of modelled solar warming of 5.9°C, 10 cm into the snowpack. For all 175 avalanches, GEM15 forecasted significantly less precipitation than observed at the weather stations, particularly with multi-day cumulative amounts. The majority of GEM15 surface wind speeds were between 0 and 10 km h−1, producing negligible wind loading amounts. The parameter values may be helpful for predicting future persistent deep slab avalanches. However, GEM output is not always representative of field conditions and should be used in conjunction with other sources.

scholarly journals The Street Air Warming Phenomenon in a High-Rise Compact City

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 402 ◽  
Author(s):  
Xiaoxue Wang ◽  
Yuguo Li ◽  
Xinyan Yang ◽  
Pak Chan ◽  
Janet Nichol ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Thermal Environment ◽  
Urban Climate ◽  
Pollutant Dispersion ◽  
Urban Morphology ◽  
Air Temperatures ◽  
Significant Difference ◽  
Sensitivity Studies ◽  
Weather Stations

The street thermal environment is important for thermal comfort, urban climate and pollutant dispersion. A 24-h vehicle traverse study was conducted over the Kowloon Peninsula of Hong Kong in summer, with each measurement period consisting of 2–3 full days. The data covered a total of 158 loops in 198 h along the route on sunny days. The measured data were averaged by three methods (direct average, FFT filter and interpolated by the piecewise cubic Hermite interpolation). The average street air temperatures were found to be 1–3 °C higher than those recorded at nearby fixed weather stations. The street warming phenomenon observed in the study has substantial implications as usually urban heat island (UHI) intensity is estimated from measurement at fixed weather stations, and therefore the UHI intensity in the built areas of the city may have been underestimated. This significant difference is of interest for studies on outdoor air temperature, thermal comfort, urban environment and pollutant dispersion. The differences were simulated by an improved one-dimensional temperature model (ZERO-CAT) using different urban morphology parameters. The model can correct the underestimation of street air temperature. Further sensitivity studies show that the building arrangement in the daytime and nighttime plays different roles for air temperature in the street. City designers can choose different parameters based on their purpose.

Radius of influence of air temperature from automated weather stations installed in complex terrain

2018 ◽  
Vol 137 (3-4) ◽  
pp. 1957-1973 ◽  
Author(s):  
Andrés Javier Peña Quiñones ◽  
Bernardo Chaves Cordoba ◽  
Melba Ruth Salazar Gutierrez ◽  
Markus Keller ◽  
Gerrit Hoogenboom
Keyword(s):  
Air Temperature ◽  
Complex Terrain ◽  
Radius Of Influence ◽  
Weather Stations

scholarly journals Cars as next generation mobile weather stations: an initial investigation

2021 ◽  
Author(s):  
Giuliano Andrea Pagani ◽  
Marcel Molendijk ◽  
Jan Willem Noteboom
Keyword(s):  
Air Temperature ◽  
Weather Conditions ◽  
Ground Temperature ◽  
Warning Systems ◽  
Traction Control ◽  
The Future ◽  
Weather Stations ◽  
Temporal And Spatial ◽  
Positive Correlation Coefficient ◽  
Digital Equipment

<p>Modern automobiles are becoming more and more “computers on the wheels” having lots of digital equipment on board. Such equipment is both for the comfort and entertainment of the passengers and for their safety. Sensors play a key role in measuring several parameters of the car performance (e.g., traction control, anti-lock breaking system) and also environmental  parameters are observed directly (e.g., air temperature) or can be somehow inferred (e.g., precipitation via windscreen wipers activity/speed).</p><p>KNMI has been provided air temperature recorded every 10 minutes by thousands of vehicles driving in the Netherlands for the period January-October 2020. We have performed an initial exploratory temporal and spatial analysis to understand the most promising periods of the day and areas where sufficient data is available to perform a more thorough data analysis in the future. Furthermore, we have performed a correlation analysis between the outside temperature measured by cars and air and ground temperature observed by official weather station sensors placed at one location on the Dutch highways. The correlation results for three randomly selected days (with different weather conditions) show a good positive correlation coefficient ranging from 0.93 to 0.76 for car and station air temperature and from 0.91 to 0.67 for car temperature and station ground temperature.</p><p>This initial exploration paves the way to the use of (OEM) car data as (mobile) weather stations. We foresee in the future to use a combination of sensed variables from cars such as air temperature, traction control, windscreen wipers activity for example to improve observations of road slipperiness and related warning systems that are not restricted to Dutch highways only.</p>

Initial Results of Monitoring the Temperature on the Facade of Office Building

2019 ◽  
Vol 887 ◽  
pp. 411-418
Author(s):  
Peter Juras ◽  
Radoslav Ponechal ◽  
Daniela Štaffenová
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Full Scale ◽  
Office Building ◽  
Wind Flow ◽  
Climate Conditions ◽  
Outdoor Climate ◽  
Measurement Units ◽  
Weather Stations ◽  
Initial Results

This paper deals with creating of the unique measurement units on the building façade, which enable the possibility to conduct a full-scale measurement of the outdoor climate parameters around the building. The façade of the Research center building, which is a part of University of Zilina campus, is equipped with 36 weather stations to measure the outdoor climate conditions and impact of the building on the approaching wind flow, air temperature distribution, solar radiance impact on the façade etc.In this article, the change of temperatures within the time and place on the facade (sides, position, time), is monitored. This takes into account the surroundings of the building and the temperature on the façade and comparison to the measured “basic” air temperature.

Monitoring of the Airflow around the Façade of an Office Building

2019 ◽  
Vol 887 ◽  
pp. 579-586
Author(s):  
Peter Juras ◽  
Radoslav Ponechal
Keyword(s):  
Temperature Distribution ◽  
High Resolution ◽  
Air Temperature ◽  
Office Building ◽  
Wind Flow ◽  
Climate Conditions ◽  
Outdoor Climate ◽  
Measurement Units ◽  
Weather Stations ◽  
Very High

This paper describes measurement units on the building façade, which enable the possibility to conduct a full-scale measurement with a very high resolution of the outdoor climate parameters around the building. The façade of the Research center building, which is a part of University of Zilina campus, is equipped with 36 weather stations to measure the outdoor climate conditions and impact of the building on the approaching wind flow and air temperature distribution, solar radiance impact on the façade, etc. In this article, the wind flow around the building in different heights is monitored, analyzed and compared to the free wind flow.

scholarly journals Intra and inter ‘local climate zone’ variability of air temperature as observed by crowdsourced citizen weather stations in Berlin, Germany

2017 ◽  
Vol 26 (5) ◽  
pp. 525-547 ◽  
Author(s):  
Daniel Fenner ◽  
Fred Meier ◽  
Benjamin Bechtel ◽  
Marco Otto ◽  
Dieter Scherer
Keyword(s):  
Air Temperature ◽  
Climate Zone ◽  
Local Climate ◽  
Weather Stations ◽  
Local Climate Zone

scholarly journals Optimality of the 2-CUSUM drift equalizer rules for detecting two-sided alternatives in the Brownian motion model

2005 ◽  
Vol 42 (4) ◽  
pp. 1183-1193 ◽  
Author(s):  
Olympia Hadjiliadis
Keyword(s):  
Brownian Motion ◽  
Companion Paper ◽  
Performance Measure ◽  
Stopping Rules ◽  
False Alarms ◽  
Motion Model ◽  
Worst Case ◽  
Detection Delay ◽  
Brownian Motion Model ◽  
Better Than

This work employs the Brownian motion model in which observations are taken sequentially. The objective is to detect a two-sided change in the constant drift by means of a stopping rule. As a performance measure, an extended Lorden criterion is used. The goal is to minimize the worst-case detection delay subject to a constraint in the frequency of false alarms. In a companion paper, attention is drawn to a first category of 2-CUSUM rules for which the harmonic mean rule holds. It is further seen that a special class of 2-CUSUM stopping rules within this category, called drift equalizer rules, perform strictly better than non-equalizer rules, according to this specific performance measure.

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