The Review of Physical Details of the Land Surface Schemes used in Numerical Weather Prediction Model
mehran
khodamoradpour
مهران خدامرادپور، دانشجوی دکتری هواشناسی، موسسه ژئوفیزیک دانشگاه تهران،
author
parviz
erannezhad
پرویز ایران نژاد ، هیئت علمی موسسه زئوفیزیک دانشگاه تهران،
author
sohrab
hajam
پرویز ایران نژاد ، هیئت علمی موسسه زئوفیزیک دانشگاه تهران،
author
robab
mashayekhi
مهران خدامرادپور، دانشجوی دکتری هواشناسی، موسسه ژئوفیزیک دانشگاه تهران،
author
text
article
2011
per
Land Surface Schemes (LSMs) are among the most important components used in climate predictions, numerical weather prediction and hydrology. Their most important task is the solution of energy and water budget in land surface. MM5 model is the fifth- generation NCAR / Penn State mesoscale model used in studying of air pollution, numerical weather prediction and hydrology. This model contains of land surface parameterization schemes, radiation, convection, boundary layer and rainfall schemes, which are connected directly to each other. The Land surface parameterization scheme in this mesoscale model contains of Bucket, Force-Restore, five- layer soil, OSU and PX schemes. In this paper, according to the importance of the land surface schemes, it has been tried to study the physics details of these land surface schemes used in mesoscale model of MM5 in detail.
Nivar
IRIMO
1735-0565
35
v.
75-74
no.
2011
3
10
https://nivar.irimo.ir/article_13203_4ea3aa5282ce4c5a6ea9dba23bd03b05.pdf
Introducing a barotropic spectral model T-21 to predict the geo-potential field
mohammadtaghi
zamaniyan
استادیار پژوهشکده هواشناسی
author
parvin
ghafariyan
دکترای هواشناسی- سازمان هواشناسی کشور
author
text
article
2011
per
The effect of accuracy of weather prediction on all aspects of normal life and special affairs is clear. Today, with optimal utilization of various models and knowledge of their accuracy, the effective steps have been taken in order to achieve this aim. The operational use of one of these models, global model, has not been done yet in our country. In this study, the barotropic model with spectral method was developed to predict the geo-potential field. Due to the high volume of information and capacity limitation of personal computers, model is performed with low resolution. Geo-potential field is predicted with leap frog scheme, and then with using the reverse of these conversions we can return to physical space from spectral space. Implementation of this model shows relatively good results. Some assumptions such as existence of baroclinic atmosphere, releasing latent heat and considering earth topography, can achieve a better prediction from this model.
Nivar
IRIMO
1735-0565
35
v.
75-74
no.
2011
11
16
https://nivar.irimo.ir/article_13204_30811973ea959760f09e72e261680c83.pdf
Statistical Analysis of Dust Phenomenon in Khuzestan Province In During Period )1996- 2005)
taghi
tavoosi
دانشیار گروه جغرافیا و برنامه ریزی محیطی دانشگاه سیستان و بلوچستان
author
mahmoud
khosravi
دانشیار گروه جغرافیا و برنامه ریزی محیطی دانشگاه سیستان و بلوچستان
author
kouhzad
raeispour
دانشجوی دوره دکترای اقلیم شناسی ـ گروه جغرافیا و برنامه ریزی محیطی دانشگاه سیستان و بلوچستان
author
text
article
2011
per
One of the natural calamities that have influenced Khuzestan Province because of geographical situation and its neighborhood with big areas of desert regions is undesirable phenomenon of dust. So for dust considering, it select 10 synoptic stations in Khuzestan province with recording data from 1996 to 2005 years. Statistical analysis is performed by using spatial distribution maps and trend diagram that are extracted from geographical information system software's (GIS) for the aim of statistical analysis. It is found that the average of dusty days in warm period is more than cold period of the year. In Khuzestan region, the number of dusty days decreases from the west to east. Spring among seasons and July among months have the most average number of dusty days. Annual trend of days associated with this phenomenon is increased during 1996 to 2005.
Nivar
IRIMO
1735-0565
35
v.
75-74
no.
2011
17
26
https://nivar.irimo.ir/article_13205_707e246494d07feee76bc743ffa58299.pdf
Analysis of Precipitation Anomaly of Northwest of Iran during Recent Decades
hosein
asakareh
دانشیار اقلیم شناسی دانشگاه زنجان
author
robab
razmi
کارشناس ارشد اقلیم شناسی دانشگاه زنجان
author
text
article
2011
per
Oscillations and changes in climatic elements due to global warming make variability in precipitation tempo-spatial distributions. Precipitation fluctuations, as one of the probable results of inter-decade climate changes, can have a significant effect in environmental and humane fields. Following the phenomena of atmosphere getting warmer and fluctuations' occurrences and changes in climate factors, we have used the daily precipitation data of 260 stations located in Northwest of Iran in the present research and made benefits of Kriging interpolation technique as an optimal interpolation technique and have changed the location data into wide range data. Besides the presentation of a clear and exact image of the general conditions of precipitation, we tried to show the normal climate conditions by using force mapping technique and precipitation deviation maps. The results showed that from the first to the fourth decade, the negative anomaly progress during all the months of the year in average annual precipitation amount is increased and the precipitation in a wide range of the region had a decreasing trend in the whole period. However, the third decade has been a seasonal precipitation phase and the fourth decade is considered to be the dry phase
Nivar
IRIMO
1735-0565
35
v.
75-74
no.
2011
27
40
https://nivar.irimo.ir/article_13206_06e574d48363d0d2e6a2573a18d2a308.pdf
Evaluating sediment transport in Shahid Bahonar port
kamran
lari
گروه فیزیک دریا-دانشگاه آزاد اسلامی واحد تهران شمال
author
masoud
torabi
گروه فیزیک دریا-دانشگاه آزاد اسلامی واحد تهران شمال
author
zohreh
khiry
دانش آموخته فیزیک دریا دانشگاه آزاد اسلامی واحد تهران شمال
author
text
article
2011
per
Sediment transport is one of the most important parameters in coastal engineering issues. It is very important to define the sediment transport rate in the sea morphology and construction of port installation, ponds and waterfronts. The issue mentioned above is so affective on anticipated design life, safety of which against sedimentation and defining the dredging period. Sediment transport in Shahid Bahonar port was evaluated in the research. First, Sediment transport was calculated using data such as wave, flow and aggregation of the region and semi – empirical methods. Then it was compared with sediment transport resulted from hydrographic maps and it is calibrated. The results demonstrated that Biker method is more accurate in the region.
Nivar
IRIMO
1735-0565
35
v.
75-74
no.
2011
41
46
https://nivar.irimo.ir/article_13207_b15a97e4c462836e741a00b66f34ca04.pdf
Review of synoptic structure for 24-hours heavy rains in Khuzestan province (during 1996-2000)
elham
mobarakhasan
دکتری هواشناسی، عضو هیات علمی گروه محیط زیست دانشگاه آزاد اسلامی واحد اهواز
author
kataun
varshosaz
دکتری محیط زیست، عضو هیات علمی گروه محیط زیست دانشگاه آزاد اسلامی واحد اهواز
author
text
article
2011
per
Khuzestan province which is located in southwest of Iran usually has low rainfall although sometimes heavy rain events records in this area. Recognition of Mechanism of forming, trajectory and humidity content of weather systems, that are associated with rain event, can have role important in distinction early flood, control flood, raceway, and watershed and reduce flood damage. First, the dates of heavy rains exceeded to 70 mm, occurring in Khuzestan province, were extracted during 1960 to 2000. Then using NCEP\NCAR reanalysis data, synoptic structure including mean sea level and geopotential height at 500 hPa levels were examined in all rain events, afterward, the composite structure was obtained by averaging in similar cases and finally synoptic structure composite was analyzed. Over all, the result showed five different synoptic patterns that can produce heavy rains in south western parts of Iran. They are called Sudan, special Sudan that extended to eastern Mediterranean, Sudan- Mediterranean low, northern Africa, Mediterranean low pressure, respectively. The results of this study also showed that in addition to Sudan lows, Mediterranean systems can produce heavy rains in south western part of Iran although their frequencies are less than Sudan lows. Also some weather systems that formed in west northern of Africa, after passing from north eastern Africa and Red sea close to Saudi Arabia and Iran, have important role to produce heavy rains in this region. Because of importance of forming area of weather systems and their trajectories in heavy rain events, it should pay more attention in determining the weather systems types that produce heavy rains in Khuzestan province.
Nivar
IRIMO
1735-0565
35
v.
75-74
no.
2011
47
56
https://nivar.irimo.ir/article_13208_cfbb0de75c18e557c1209294a132ce71.pdf
Investigation Of Seasonal Changes Of Temperature Profile For Studying Double Diffusive Convection In The Strait of Hormuz Using a 3-D Numerical Model
maryam
ahmadi
دانشجوی کارشناسی ارشد آبیاری و زهکشی گروه مهندسی آب دانشکده کشاورزی دانشگاه رازی
author
bahman
farhadi
دکترای آبیاری و زهکشی، استادیار گروه مهندسی آب دانشکده کشاورزی دانشگاه رازی
author
text
article
2011
per
The aim of this study is to analyze the vertical profile of temperature for studying the double diffusive convection using a three-dimensional numerical model in the east of Persian Gulf. Vertical profile of temperature is the precise and explicit description of temperature in various layer of ocean with considering the seasonal variation. The Persian Gulf, particularly in the Strait of Hormuz area is one of the most important region in terms of marine environmental, ocean sciences, economics, commercial and military, therefore description of seasonal cycle of temperature is important in this region. Temperature profile has an important role in physical oceanography, marine chemistry and biology. In this study vertical profile of temperature and its spatial distribution in various layer of Persian Gulf were analyze using a 3-D numerical model (COHERENS) during the year. For reaching the steady state of Physical feature such as temperature and salinity, the model was run for five year in Persian Gulf. The results of model were comparing with field observations of Jones and Zentop that get from Strait of Hormuz, which are agreement with our results and show that in the spring and summer there is a strong thermal difference between surface and deep layers, so that in some parts, it reaches 12. As already mentioned this severe difference, causes to strong stratification of density and then leads to static stability of currents in upper layer. In autumn by decreasing the surface layer temperature, the heat transfer from deep layers to the surface occurred because of convective currents that leads to significant decrease the temperature of deep layer and also decrease of sharp contrast of summer temperature between surface and bottom that cause to predict of convection in the Strait of Hormuz.
Nivar
IRIMO
1735-0565
35
v.
75-74
no.
2011
57
66
https://nivar.irimo.ir/article_13209_d5c49d6442c2beb9bcd6eb2af07a98c0.pdf