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Ali Mohammad Khorshiddoust, Mehdi Asadi, Hassan Hajimohammadi ,
Volume 4, Issue 2 (7-2017)
Volume 4, Issue 2 (7-2017)
Abstract
Thunderstorms are among the first meteorological phenomena, which have attracted human attention. Thunderstorms with rain showers and storms accompanied by hail and their role in causing sudden floods, both in terms of agriculture and human and financial losses, have been noticed by researchers. Rain hail of bullets or pieces of ice ascends very high in elevation due to the weather conditions along with electrical features occurrence. Hail grains or pieces of ice with diameters of 5 to 50 mm occasionally take longer time to be made up. Strong growth of hail through severe and repeated vertical movements of air in cumulonimbus clouds freezes the absorbed water droplets around hailstones. Few thunderstorm hails arrive on land many of which even contain no hail even in the most suitable parts of the clouds. The creation and hail falling, despite being warm and humid in the lower atmosphere and the ascending of clouds condensed with respect to the altitude and cold weather are coupled with the continuing maximum air instability. Because of the importance of hail event, studies on the formation and growth of hail in different countries are conducted for its prediction. In connection with hail and hail storms extensive research work has been carried out in including: Costa et al. (2001), Simonov and Gergiev (2003), Whiteman (2003) and Sterling (2003).
To investigate the thunderstorm and hails occurred in the region, we examined weather conditions. Initially the values of pressure, temperature and dew point temperature by the radiosonde measurements in different layers of the atmosphere were studied and the plotted graphs were obtained from NOAA. In the next stage for a closer look at weather conditions parameters like air temperature (Air), sea level pressure (SLP), geo-potential height (Hgt), specific humidity (Shum), vertical velocity (Omega) orbital wind component (Uwnd) and meridional wind component (Vwnd) were analyzed. The data records were collected from the website of the National Center for Environmental Prediction and National Climate Science (NCEP/NCAR). Instability investigation in the atmosphere for different levels of instability indices was applied.
Investigation on instability indices showed that on the first day the ascending index values (LI) were at 2-, which are the values added in the next two days. These conditions prove that the atmospheric turbulence is intensified in the days after the first day. By examining the thickness of the atmosphere it is seen on the Azerbaijan area On 16 July that on 5785 geo-potential meters the next day was associated with reduced 51 meter geo-potential added value at the third day. The results also revealed that the atmospheric precipitation of water values is calculated on a three-day index value of 17, 18 and more than 23 mm per day. To check the status of stormy weather index (SWEA) and K we found that the occurrence of thunderstorms in that area started on 16 July, approaching the end of high value added indicators that show strengthening of storms and their destructive mechanism in the day after the end of the other.
Investigation of thermodynamic charts showed that rapid convective ascent of available potential energy depending on the weather in the region has been so high and caused the weather to approach three days in advance to the upper layers of the atmosphere and atmospheric turbulence was created for the region. Examining the rainfall map of geo-potential height and vortices in 500 hPa on the first day exhibited that tthunderstorms were the result of interactions of the atmosphere, so that in middle levels the strong condensation of location with a range of more than 25 degrees of latitude on Caspian Sea was created and polar latitudes spread to nearby areas. On the second day, high-altitude thunderstorm in the core atmospheric cut-off formed on the Caspian Sea on the East of Turkey, northern Iraq and North West of Iran created the geo-potential height of the center of the 5750 geopotential meter. On the third day, atmospheric cut-off core to cut area of low pressure was made on the maximum positive vortices in the climate system. Conditions over the surface in the first day of the storm in the region indicated very strong contour of low pressure formed in the North East to West and North West of Saudi Arabia. In front of the two sides one of on Mediterranean Sea and other northern Russia, the contour of the pressure was imported into the Middle East.
To investigate the thunderstorm and hails occurred in the region, we examined weather conditions. Initially the values of pressure, temperature and dew point temperature by the radiosonde measurements in different layers of the atmosphere were studied and the plotted graphs were obtained from NOAA. In the next stage for a closer look at weather conditions parameters like air temperature (Air), sea level pressure (SLP), geo-potential height (Hgt), specific humidity (Shum), vertical velocity (Omega) orbital wind component (Uwnd) and meridional wind component (Vwnd) were analyzed. The data records were collected from the website of the National Center for Environmental Prediction and National Climate Science (NCEP/NCAR). Instability investigation in the atmosphere for different levels of instability indices was applied.
Investigation on instability indices showed that on the first day the ascending index values (LI) were at 2-, which are the values added in the next two days. These conditions prove that the atmospheric turbulence is intensified in the days after the first day. By examining the thickness of the atmosphere it is seen on the Azerbaijan area On 16 July that on 5785 geo-potential meters the next day was associated with reduced 51 meter geo-potential added value at the third day. The results also revealed that the atmospheric precipitation of water values is calculated on a three-day index value of 17, 18 and more than 23 mm per day. To check the status of stormy weather index (SWEA) and K we found that the occurrence of thunderstorms in that area started on 16 July, approaching the end of high value added indicators that show strengthening of storms and their destructive mechanism in the day after the end of the other.
Investigation of thermodynamic charts showed that rapid convective ascent of available potential energy depending on the weather in the region has been so high and caused the weather to approach three days in advance to the upper layers of the atmosphere and atmospheric turbulence was created for the region. Examining the rainfall map of geo-potential height and vortices in 500 hPa on the first day exhibited that tthunderstorms were the result of interactions of the atmosphere, so that in middle levels the strong condensation of location with a range of more than 25 degrees of latitude on Caspian Sea was created and polar latitudes spread to nearby areas. On the second day, high-altitude thunderstorm in the core atmospheric cut-off formed on the Caspian Sea on the East of Turkey, northern Iraq and North West of Iran created the geo-potential height of the center of the 5750 geopotential meter. On the third day, atmospheric cut-off core to cut area of low pressure was made on the maximum positive vortices in the climate system. Conditions over the surface in the first day of the storm in the region indicated very strong contour of low pressure formed in the North East to West and North West of Saudi Arabia. In front of the two sides one of on Mediterranean Sea and other northern Russia, the contour of the pressure was imported into the Middle East.
Faryad Shayesteh, , ,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
The role of tropospheric vertical anomalies in rainfall solid Case study: the hazard of hail in Kermanshah
Climate risks is one of the Types of hazards that damages human communities such as the phenomenon of hail, in the micro-scale, it causes financial losses and casualties. Hail is associated to the atmospheric elements and geo-location factors. Whenever weather conditions and appropriate physical processes are combined with geo-location creates and intensifies this phenomenon.
Losses resulted from hail has been more effective in the agricultural sector and in the effect of damaging the crops When growth and budding. However, it disorders in other sectors such as, blemishing residential buildings, Losing large and small animals also, damaging to the aircraft flight and its components. Hail considerable damage in Kermanshah province every year so that Farmers insure their crops against this Phenomenon and the government will incur heavy costs for
damage that is inflicted on the sector of activity.
Research methodology
The current weather data has been used with 3-hour intervals in the statistical period of 65 years (1951 to 2016) from synoptic stations of Kermanshah Province that includes the stations of Kermanshah, West Islamabad, Ravansar, Kangavar, West Gilan, and Sar-e-Pole-Zahab.
Among the 100 present weather code, Codes 99, 96, 91, 90, 89, 87 and 27 have been considered that including hail phenomenon by varying intensities and includes any appearance of this phenomenon in Hours scout and three hours earlier. Then, based on the above code, Were coded in Excel to identifies Codes 96, 91, 90, 89, 87 and 27 When entering from the Meteorological Data To the desired program among Group VII of the data, And when the written code, were identified, Hail days were marked.
Given that in this study Hail is studied regarding the synoptic conditions and temperature anomalies. Therefore, for the synoptic situation, Pressure data, vorticity, Special moisture, Components U and V, Omega transverse profile And outgoing longwave radiation, And for the temperature anomaly, Temperature and isothermal anomalies components Were getting from esrl.noaa.gov/psd site And using the software Grads were drawn maps for a selected day To determine the formation of hail.
Commentaries Results
The frequency of occurrence of hail has reached 187 in the period 65 years in Kermanshah province. This phenomenon generally occurs from mid-September to mid-June. The most number has been in Kermanshah station and the Least in Sar-Pol-Zahab station.
April has had the highest number of hail frequencies in Kermanshah province and the greatest losses in the month related to the agricultural sector. Therefore, Select System hail seems essential to examine how the temperature anomalies and the formation of hail in the month.
On the day of the event, trough hail has been formed in the East Mediterranean.Wrying the trough axis From North East to South West resulted in cold air from high latitudes to the East of the Mediterranean.
The establishment of trough in the middle and low pressure level in sea level and its following Convergence in the balance has created positive omega until balance of 200 hPa and most serious it is at the level of 400 hPa. Negative omega has maintained its association from ground surface until High levels in the study area.
The airflow of vorticity balance 1000 and 500 Hpa Suggests vorticity positive settlement area on the case study. Establishment of short wave in the vicinity of the study area and intensifying ascending conditions also Prolong Positive trough conditions from surface of Earth until 500hpa balance have been The necessary dynamic conditions for Hail in this day.
Special moisture and wind Vector with 700hpa balance of Moisture transfer has been done by two opposite vorticity system. Trough rotary motion Based on the Mediterranean and along the Red Sea on the one hand and Moving anticyclone over the Arabian Sea And the Persian Gulf and Oman Sea on the other, have conveyed Moisture of all moisture sources from The seas around to The study area.
Also OLR anomalies for the hail event day indicates being Negative in the study area and the sharp decline of Outgoing longwave in this day Compared to its long-term average And hence the conditions of cloudiness and the formation and intensification of convection has been provided.
1000 hpa positive anomaly 2 ° is representative the Higher than the average temperature conditions and in the 500hpa anomaly balance Minus 2 degrees Celsius is representative Lower than normal temperatures in the balance. These factors aggravate the vertical temperature gradient in the study area these days. 20+ degrees Celsius the Isothermal curve and -20 ° C. Respectively, the levels of 1000 and 500 Drawn to the area of study And has created a large temperature difference Between the upper and lower levels.
Keywords: Synoptic analysis, Hail hazard, Tropospheric anomalies, Vorticity, Kermanshah Province
Climate risks is one of the Types of hazards that damages human communities such as the phenomenon of hail, in the micro-scale, it causes financial losses and casualties. Hail is associated to the atmospheric elements and geo-location factors. Whenever weather conditions and appropriate physical processes are combined with geo-location creates and intensifies this phenomenon.
Losses resulted from hail has been more effective in the agricultural sector and in the effect of damaging the crops When growth and budding. However, it disorders in other sectors such as, blemishing residential buildings, Losing large and small animals also, damaging to the aircraft flight and its components. Hail considerable damage in Kermanshah province every year so that Farmers insure their crops against this Phenomenon and the government will incur heavy costs for
damage that is inflicted on the sector of activity.
Research methodology
The current weather data has been used with 3-hour intervals in the statistical period of 65 years (1951 to 2016) from synoptic stations of Kermanshah Province that includes the stations of Kermanshah, West Islamabad, Ravansar, Kangavar, West Gilan, and Sar-e-Pole-Zahab.
Among the 100 present weather code, Codes 99, 96, 91, 90, 89, 87 and 27 have been considered that including hail phenomenon by varying intensities and includes any appearance of this phenomenon in Hours scout and three hours earlier. Then, based on the above code, Were coded in Excel to identifies Codes 96, 91, 90, 89, 87 and 27 When entering from the Meteorological Data To the desired program among Group VII of the data, And when the written code, were identified, Hail days were marked.
Given that in this study Hail is studied regarding the synoptic conditions and temperature anomalies. Therefore, for the synoptic situation, Pressure data, vorticity, Special moisture, Components U and V, Omega transverse profile And outgoing longwave radiation, And for the temperature anomaly, Temperature and isothermal anomalies components Were getting from esrl.noaa.gov/psd site And using the software Grads were drawn maps for a selected day To determine the formation of hail.
Commentaries Results
The frequency of occurrence of hail has reached 187 in the period 65 years in Kermanshah province. This phenomenon generally occurs from mid-September to mid-June. The most number has been in Kermanshah station and the Least in Sar-Pol-Zahab station.
April has had the highest number of hail frequencies in Kermanshah province and the greatest losses in the month related to the agricultural sector. Therefore, Select System hail seems essential to examine how the temperature anomalies and the formation of hail in the month.
On the day of the event, trough hail has been formed in the East Mediterranean.Wrying the trough axis From North East to South West resulted in cold air from high latitudes to the East of the Mediterranean.
The establishment of trough in the middle and low pressure level in sea level and its following Convergence in the balance has created positive omega until balance of 200 hPa and most serious it is at the level of 400 hPa. Negative omega has maintained its association from ground surface until High levels in the study area.
The airflow of vorticity balance 1000 and 500 Hpa Suggests vorticity positive settlement area on the case study. Establishment of short wave in the vicinity of the study area and intensifying ascending conditions also Prolong Positive trough conditions from surface of Earth until 500hpa balance have been The necessary dynamic conditions for Hail in this day.
Special moisture and wind Vector with 700hpa balance of Moisture transfer has been done by two opposite vorticity system. Trough rotary motion Based on the Mediterranean and along the Red Sea on the one hand and Moving anticyclone over the Arabian Sea And the Persian Gulf and Oman Sea on the other, have conveyed Moisture of all moisture sources from The seas around to The study area.
Also OLR anomalies for the hail event day indicates being Negative in the study area and the sharp decline of Outgoing longwave in this day Compared to its long-term average And hence the conditions of cloudiness and the formation and intensification of convection has been provided.
1000 hpa positive anomaly 2 ° is representative the Higher than the average temperature conditions and in the 500hpa anomaly balance Minus 2 degrees Celsius is representative Lower than normal temperatures in the balance. These factors aggravate the vertical temperature gradient in the study area these days. 20+ degrees Celsius the Isothermal curve and -20 ° C. Respectively, the levels of 1000 and 500 Drawn to the area of study And has created a large temperature difference Between the upper and lower levels.
Keywords: Synoptic analysis, Hail hazard, Tropospheric anomalies, Vorticity, Kermanshah Province
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