scholarly journals Validation of CloudSat-CPR Derived Precipitation Occurrence and Phase Estimates across Canada

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 295
Author(s):  
Rithwik Kodamana ◽  
Christopher G. Fletcher
Keyword(s):  
Probability Of Detection ◽  
The Arctic ◽  
Satellite Monitoring ◽  
Temperature Sensitive ◽  
Weather Information ◽  
Precipitation Occurrence ◽  
Large Databases ◽  
Precipitation Gauge ◽  
Solid Liquid ◽  
Precipitation Phase

Snowfall affects the terrestrial climate system at high latitudes through its impacts on local meteorology, freshwater resources and energy balance. Precise snowfall monitoring is essential for cold countries such as Canada, and particularly in temperature-sensitive regions such as the Arctic; however, its size and remote location means the precipitation gauge network there is sparse. While satellite remote sensing of snowfall from instruments such as CloudSat-CPR offers a potential solution, satellite detection of precipitation phase has not been systematically evaluated across Canada. In this study, CloudSat-based precipitation occurrence and phase retrievals were validated at 26 stations across Canada maintained by Environment and Climate Change Canada (ECCC). Probability of Detection (POD), defined as the percentage agreement between coincident CloudSat and human-observed present weather information for precipitation (solid, liquid or no precipitation), and False Alarm Ratio (FAR) were used as the primary metrics for validation. The mean POD (FAR) for precipitation occurrence across Canada is 65.5% ± 4.3 (31.4% ± 5.1) and for no precipitation is 90.6% ± 1.4 (11% ± 2.5). The results show lower rates of detection under cloudier skies, in the presence of (freezing) drizzle and for lighter snowfall, which may be explained by a large number of false-positives due to CloudSat-CPR’s high instrumental sensitivity. When CloudSat correctly detects the occurrence of precipitation, it shows uniformly high POD (>80%) and low FAR (<10%) for classifying the phase of precipitation. Large databases of coincident ground and satellite measurements allow us to provide a new estimate of around 9% for the frequency of virga events, a factor of two smaller than a previous estimate for the Arctic. The results from this study show that CloudSat has useful accuracy in detecting precipitation occurrence and very high accuracy at classifying precipitation phase, over diverse climate zones across Canada. As such, there is significant potential for satellite monitoring of snowfall in remote, cold regions.

scholarly journals Use of satellite data for detecting icebergs and evaluating the iceberg threats

2018 ◽  
Vol 58 (4) ◽  
pp. 537-551 ◽  
Author(s):  
I. A. Bychkova ◽  
V. G. Smirnov
Keyword(s):  
Satellite Data ◽  
Radar Data ◽  
Arctic Shelf ◽  
The Arctic ◽  
Satellite Monitoring ◽  
Landsat 8 ◽  
Space Resolution ◽  
Detection Techniques ◽  
Satellite Radar ◽  
High Space

Te methods of satellite monitoring of dangerous ice formations, namely icebergs in the Arctic seas, representing a threat to the safety of navigation and economic activity on the Arctic shelf are considered. Te main objective of the research is to develop methods for detecting icebergs using satellite radar data and high space resolution images in the visible spectral range. Te developed method of iceberg detection is based on statistical criteria for fnding gradient zones in the analysis of two-dimensional felds of satellite images. Te algorithms of the iceberg detection, the procedure of the false target identifcation, and determination the horizontal dimensions of the icebergs and their location are described. Examples of iceberg detection using satellite information with high space resolution obtained from Sentinel-1 and Landsat-8 satellites are given. To assess the iceberg threat, we propose to use a model of their drif, one of the input parameters of which is the size of the detected objects. Tree possible situations of observation of icebergs are identifed, namely, the «status» state of objects: icebergs on open water; icebergs in drifing ice; and icebergs in the fast ice. At the same time, in each of these situations, the iceberg can be grounded, that prevents its moving. Specifc features of the iceberg monitoring at various «status» states of them are considered. Te «status» state of the iceberg is also taken into account when assessing the degree of danger of the detected object. Te use of iceberg detection techniques based on satellite radar data and visible range images is illustrated by results of monitoring the coastal areas of the Severnaya Zemlya archipelago. Te approaches proposed to detect icebergs from satellite data allow improving the quality and efciency of service for a wide number of users with ensuring the efciency and safety of Arctic navigation and activities on the Arctic shelf.

Satellite Monitoring of Icebergs in the Arctic Seas

2019 ◽  
Vol 44 (4) ◽  
pp. 262-267
Author(s):  
V. G. Smirnov ◽  
I. A. Bychkova ◽  
S. V. Mikhal’tseva ◽  
E. V. Platonova
Keyword(s):  
The Arctic ◽  
Satellite Monitoring ◽  
Arctic Seas

scholarly journals Arctic Fog Detection Using Infrared Spectral Measurements

2019 ◽  
Vol 36 (8) ◽  
pp. 1643-1656
Author(s):  
Li Yi ◽  
King-Fai Li ◽  
Xianyao Chen ◽  
Ka-Kit Tung
Keyword(s):  
Sea Ice ◽  
Chukchi Sea ◽  
Open Water ◽  
Detection Algorithm ◽  
Probability Of Detection ◽  
Satellite Observations ◽  
The Arctic ◽  
Water Surface Area ◽  
Infrared Spectral ◽  
Fog Detection

AbstractThe rapid increase in open-water surface area in the Arctic, resulting from sea ice melting during the summer likely as a result of global warming, may lead to an increase in fog [defined as a cloud with a base height below 1000 ft (~304 m)], which may imperil ships and small aircraft transportation in the region. There is a need for monitoring fog formation over the Arctic. Given that ground-based observations of fog over Arctic open water are very sparse, satellite observations may become the most effective way for Arctic fog monitoring. We developed a fog detection algorithm using the temperature difference between the cloud top and the surface, called ∂T in this work. A fog event is said to be detected if ∂T is greater than a threshold, which is typically between −6 and −12 K, depending on the time of the day (day or night) and the surface types (open water or sea ice). We applied this method to the coastal regions of Chukchi Sea and Beaufort Sea near Barrow, Alaska (now known as Utqiaġvik), during the months of March–October. Training with satellite observations between 2007 and 2014 over this region, the ∂T method can detect Arctic fog with an optimal probability of detection (POD) between 74% and 90% and false alarm rate (FAR) between 5% and 17%. These statistics are validated with data between 2015 and 2016 and are shown to be robust from one subperiod to another.

Satellite-derived spatiotemporal patterns of environmental changes caused by 2018-2019 wildfires in Arctic-Boreal Russia

2020 ◽  
Author(s):  
Elena Cherepanova ◽  
Valery Bondur ◽  
Viktor Zamshin ◽  
Natalia Feoktistova
Keyword(s):  
Time Series ◽  
Greenhouse Gases ◽  
Forest Fires ◽  
Environmental Changes ◽  
Negative Impact ◽  
Spatiotemporal Patterns ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Satellite Monitoring ◽  
Local Conditions

&lt;p&gt;Forest fires affect environmental changes both directly, changing the type of land cover, causing local and regional air pollution through emissions of greenhouse gases and aerosols, and indirectly through a secondary effect on atmospheric, soil and hydrological processes. The increase in the number and area of uncontrolled wildfires, the degradation of permafrost in high latitude areas leads to a change in the balance of greenhouse gases in the atmosphere, and it results in the negative impact on the Earth&amp;#8217;s climatic system.&lt;/p&gt;&lt;p&gt;This study examined the Arctic-Boreal territories of the Russian Federation, where huge forest fires were observed in 2018-2019. In most of these areas, forest fire detection is carried out only by means of the satellite monitoring without aviation support. The sparsely populated and inaccessible territories are a major factor of the rapid spread of fires over large areas. Most of the forest areas in the region are so-called control zones, where the authorities may decide not to extinguish the fires if they do not threaten settlements and economic facilities, and consider the salvation of forests economically unprofitable. However, there is no reliable data on the environmental consequences of large forest fires in the Arctic-Boreal territories.&lt;/p&gt;&lt;p&gt;Satellite monitoring of wildfires provides the detection of fire locations, an assessment of their area and burning time. In our study, we used various indices calculated from remote sensing data for the pre-fire and post-fire periods to identify the spatiotemporal patterns of environmental change caused by large wildfires. The Sentinel 5 TROPOMI time series have been analyzed for the short-term and long-term atmospheric composition anomalies detection caused by forest fires in the region. In the process of comparing the methane concentrations time series for the 2018- 2019 fire seasons the constantly high values anomaly zones were found. We believe that these anomalies are resulting from Sentinel-5 CH4 algorithm constrains, which requires additional work on data validation with relation to the local conditions.&lt;/p&gt;&lt;p&gt;The reported study was funded by RFBR, MOST (China) and DST (India) according to the research project &amp;#8470; 19-55-80021&lt;/p&gt;

scholarly journals Wind Forecasts for Rocket and Balloon Launches at the Esrange Space Center Using the WRF Model

2018 ◽  
Vol 33 (3) ◽  
pp. 813-833
Author(s):  
Ricardo Fonseca ◽  
Javier Martín-Torres ◽  
Kent Andersson
Keyword(s):  
Critical Role ◽  
Wrf Model ◽  
Arctic Region ◽  
Probability Of Detection ◽  
The Arctic ◽  
Weather Research And Forecasting ◽  
Sounding Rockets ◽  
Convective Model ◽  
Nonlocal Asymmetric ◽  
The Arctic Region

Abstract High-altitude balloons and rockets are regularly launched at the Esrange Space Center (ESC) in Kiruna, Sweden, with the aim of retrieving atmospheric data for meteorological and space studies in the Arctic region. Meteorological conditions, particularly wind direction and speed, play a critical role in the decision of whether to go ahead with or postpone a planned launch. Given the lack of high-resolution wind forecasts for this remote region, the Weather Research and Forecasting (WRF) Model is used to downscale short-term forecasts given by the Global Forecast System (GFS) for the ESC for six 5-day periods in the warm, cold, and transition seasons. Three planetary boundary layer (PBL) schemes are considered: the local Mellor–Yamada–Janjić (MYJ), the nonlocal Yonsei University (YSU), and the hybrid local–nonlocal Asymmetric Convective Model 2 (ACM2). The ACM2 scheme is found to provide the most skillful forecasts. An analysis of the WRF Model output against the launch criteria for two of the most commonly launched vehicles, the sounding rockets Veículo de Sondagem Booster-30 (VSB-30) and Improved Orion, reveals probability of detection (POD) values that always exceeds 60% with the false alarm rate (FAR) generally below 50%. It is concluded that the WRF Model, in its present configuration, can be used to generate useful 5-day wind forecasts for the launches of these two rockets. The conclusions reached here are applicable to similar sites in the Arctic and Antarctic regions.

scholarly journals Software Technologies in Satellite Monitoring of the Arctic Ice Cover

2015 ◽  
Vol 8 (6) ◽  
pp. 680-689 ◽  
Author(s):  
Vasilii V. Asmus ◽  
◽  
Vladimir A. Krovotyntsev ◽  
Valerii P. Pyatkin ◽  
◽  
...  
Keyword(s):  
Ice Cover ◽  
The Arctic ◽  
Satellite Monitoring ◽  
Arctic Ice

scholarly journals Evaluation of the WMO-SPICE transfer functions for adjusting the wind bias in solid precipitation measurements

2019 ◽  
Author(s):  
Craig D. Smith ◽  
Amber Ross ◽  
John Kochendorfer ◽  
Michael E. Earle ◽  
Mareile Wolff ◽  
...  
Keyword(s):  
Performance Metrics ◽  
Transfer Functions ◽  
Pearson Correlation ◽  
Solid Precipitation ◽  
Extensive Field ◽  
The World ◽  
Precipitation Gauge ◽  
Automated Instruments ◽  
Precipitation Phase ◽  
Wind Bias

Abstract. The World Meteorological Organization (WMO) Solid Precipitation Inter-Comparison Experiment (SPICE) involved extensive field intercomparisons of automated instruments for measuring snow during the 2013/2014 and 2014/2015 winter seasons. A key outcome of SPICE was the development of transfer functions for the wind bias adjustment of solid precipitation measurements using various precipitation gauge and windshield configurations. Due to the short intercomparison period, the dataset was not sufficiently large to develop and evaluate transfer functions using independent precipitation measurements. The present analysis uses data collected at eight SPICE sites over the 2015/2016 and 2016/2017 winter periods, comparing 30-minute adjusted and unadjusted measurements from Geonor T-200B3 and OTT Pluvio2 precipitation gauges in different shield configurations to the WMO Double Fence Automated Reference (DFAR) for the verification of the transfer function. Performance is assessed in terms of relative total catch (RTC), root mean square error (RMSE), and Pearson correlation (r), and Nash-Sutcliffe Efficiency (NSE) for all precipitation types, and for snow only. The evaluation shows that the performance varies substantially by site. Adjusted RTC varies from 54 % to 123 %, RMSE from 0.07 mm to 0.38 mm, and r from 0.28 to 0.94 and NSE from −1.88 to 0.89, depending on precipitation phase, site, and gauge configuration. Generally, windier sites such as Haukeliseter (Norway) and Bratt's Lake (Canada) exhibit a net under-adjustment (17 % to 46 %), while the less windy sites such as Sodankylä (Finland) and Caribou Creek (Canada) exhibit a net over-adjustment (2 % to 23 %). Although the application of transfer functions is necessary to mitigate wind bias in solid precipitation measurements, especially at windy sites and for unshielded gauges, the inconsistency in the performance metrics among sites suggests that the functions be applied with caution.

Antarctic Peninsula warming and precipitation phase transition during atmospheric river events

2021 ◽  
Author(s):  
Irina Gorodetskaya ◽  
Penny Rowe ◽  
Xun Zou ◽  
Anastasia Chyhareva ◽  
Svitlana Krakovska ◽  
...  
Keyword(s):  
Phase Transition ◽  
Antarctic Peninsula ◽  
Moisture Transport ◽  
Large Scale ◽  
The Arctic ◽  
Polar Regions ◽  
Near Surface ◽  
Depth Analysis ◽  
Heat And Moisture ◽  
Precipitation Phase

&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Polar amplification has been pronounced in the Arctic with near-surface air temperatures increasing at more than twice the global warming rate d&lt;/span&gt;uring the last several decades&lt;span lang=&quot;en-US&quot;&gt;. At the same time, over Antarctica temperature trends have exhibited a large regional variability. In particular, the &lt;/span&gt;Antarctic Peninsula (AP) &lt;span lang=&quot;en-US&quot;&gt;stands out as having a &lt;/span&gt;warming&lt;span lang=&quot;en-US&quot;&gt; rate much higher than&lt;/span&gt; the rest of the Antarctic ice sheet and other land areas in the Southern Hemisphere (SH)&lt;span lang=&quot;en-US&quot;&gt;.&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;F&lt;/span&gt;uture projections indicate that &lt;span lang=&quot;en-US&quot;&gt;warming and ice loss will intensify in both polar regions with important impacts&lt;/span&gt; globally. In addition to the warming amplification, there has been also an enhancement of the polar water cycle with increase&lt;span lang=&quot;en-US&quot;&gt;s&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;in &lt;/span&gt;poleward moisture transport and precipitation in both polar regions. An important process linking warming and precipitation enhancement is a shift towards more frequent rainfall compared to snowfall&lt;span lang=&quot;en-US&quot;&gt;. F&lt;/span&gt;uture projections show that the rain fraction will significantly increase in coastal Antarctica, especially in the AP. Atmospheric rivers (ARs), long corridors of intense moisture transport from subtropical and mid-latitude regions poleward, are known for &lt;span lang=&quot;en-US&quot;&gt;their &lt;/span&gt;prominent role in &lt;span lang=&quot;en-US&quot;&gt;both &lt;/span&gt;heat and moisture transport with impacts ranging from intense precipitation to temperature records and major melt events in Antarctica.&lt;span lang=&quot;en-US&quot;&gt; Limited observations have hampered process understanding and correct representation of these extreme events in models.&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;This presentation will give an overview of the &lt;/span&gt;enhanced observations targeting ARs in the A&lt;span lang=&quot;en-US&quot;&gt;P&lt;/span&gt; (&lt;span lang=&quot;en-US&quot;&gt;including &lt;/span&gt;surface meteorology, radiosonde, cloud and precipitation remote sensing, &lt;span lang=&quot;en-US&quot;&gt;and &lt;/span&gt;radiative fluxes) as part of the &lt;span lang=&quot;en-US&quot;&gt;Year of Polar Prediction (&lt;/span&gt;YOPP&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;-SH international collaborative effort&lt;span lang=&quot;en-US&quot;&gt;. &lt;/span&gt;In-depth analysis of transport of heat and moisture, &lt;span lang=&quot;en-US&quot;&gt;atmospheric vertical structure, &lt;/span&gt;cloud properties&lt;span lang=&quot;en-US&quot;&gt; and precipitation phase transition from snowfall to rainfall &lt;/span&gt;during selected &lt;span lang=&quot;en-US&quot;&gt;AR &lt;/span&gt;case&lt;span lang=&quot;en-US&quot;&gt;s&lt;/span&gt; will be&lt;span lang=&quot;en-US&quot;&gt; presented and compared with ERA5 reanalysis and high-resolution Polar-WRF model simulations&lt;/span&gt;.&lt;span lang=&quot;en-US&quot;&gt; We will highlight three different local regimes around the AP: large-scale precipitation over the Southern Ocean north of the AP, orographic enhancement of precipitation in the western AP and the role of foehn, cloud/precipitation clearing and temperature increase in the northeastern AP. &lt;/span&gt;&lt;/p&gt;

From Living Water to the “Water of Death”: Implicating Social Resilience in Northeastern Siberia

2013 ◽  
Vol 17 (2) ◽  
pp. 115-124 ◽  
Author(s):  
Susan A. Crate
Keyword(s):  
Global Climate ◽  
Belief System ◽  
The Arctic ◽  
Social Resilience ◽  
The North ◽  
Northeastern Siberia ◽  
Precipitation Regimes ◽  
Cattle Breeders ◽  
Local Water ◽  
Solid Liquid

Rural inhabitants of the Arctic sustain their way of life via refined adaptations to the extreme climate of the North, and subsequent generations continue to adapt. Viliui Sakha, Turkic-speaking horse and cattle breeders of northeastern Siberia, Russia, have been successful through their ancestral adaptations to local water access, in both a solid and liquid state, at specific times and in specific amounts. Viliui Sakha’s activities to access and utilize water are grounded in a belief system where water is spirit-filled, gives life, and can interplay with death. In the context of contemporary global climate change, water’s solid-liquid balance is disrupted by changing seasonal patterns, altered precipitation regimes, and an overall “softening” of the extreme annual temperature range. Inhabitants are finding ways to adapt but at increasing labor and resource costs. In this paper, I analyze Viliui Sakha’s adaptations to altered water regimes on both the physical and cosmological levels to grasp how water is understood in Sakha’s belief system as the water of life, how it becomes “the water of death,” and the implications for social resilience.

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