scholarly journals Synoptic Analysis of Climatic Hazards in Southwestern Iran (Case study: flood generating heavy precipitation of Azar 1391)

2016 ◽  
Vol 2 (4) ◽  
pp. 31-46 ◽  
Author(s):  
Amir hossien Halabian ◽  
Fereshteh hossienalipour jazi ◽  
◽  
Keyword(s):  
Heavy Precipitation ◽  
Synoptic Analysis ◽  
Climatic Hazards ◽  
Southwestern Iran

Synoptic analysis and mesoscale numerical modelling of heavy precipitation: a case study of flash flood event in Kota Kinabalu, Malaysia

2019 ◽  
Vol 132 (2) ◽  
pp. 181-201
Author(s):  
Jackson Hian-Wui Chang ◽  
S. S. K. Kong ◽  
Justin Sentian ◽  
Jedol Dayou ◽  
Fuei-Pien Chee
Keyword(s):  
Numerical Modelling ◽  
Flash Flood ◽  
Heavy Precipitation ◽  
Flood Event ◽  
Synoptic Analysis

Sedimentological, Geochemical and Hydrogeochemical Studies of Alluvial Fans for Mineral and Environmental Purposes (Case Study of Southwestern Iran)

2021 ◽  
Vol 56 (1) ◽  
pp. 89-112
Author(s):  
Saeid Pourmorad ◽  
Reza Mousavi Harami ◽  
Ali Solgi ◽  
Mohsen Aleali
Keyword(s):  
Alluvial Fans ◽  
Southwestern Iran

Soil and nutrient losses due to root crops harvesting: a case study from southwestern Iran

2017 ◽  
Vol 63 (11) ◽  
pp. 1523-1534 ◽  
Author(s):  
Mohammad Faraji ◽  
Alireza Amirian Chakan ◽  
Masoud Jafarizadeh ◽  
Ali Mohammadian Behbahani
Keyword(s):  
Nutrient Losses ◽  
Root Crops ◽  
Southwestern Iran

scholarly journals Analyse météorologique de l'évolution temporelle du risque d'inondation à Douala (Cameroun)

2021 ◽  
pp. 047
Author(s):  
Rinelle Djiondo Ngongang ◽  
Lucie Angennes Djiotang Tchotchou ◽  
Boniface Elvis Ossombo ◽  
Brice Baudouin Sandjeu Wandjie ◽  
André Lenouo
Keyword(s):  
Urban Areas ◽  
Meteorological Data ◽  
Maximum Flow ◽  
Synoptic Situation ◽  
Change Of State ◽  
Climatic Hazards ◽  
Base De Données ◽  
The Press ◽  
Urban Risk

Cet article analyse l'évolution des inondations dans la ville de Douala à partir des méthodes permettant de calculer une valeur de débit maximum à l'aide des données météorologiques sur une période de 35 ans (1985-2019). Une base de données sur les inondations créée à l'aide d'informations issues de la presse montre que Douala est fréquemment inondée durant la saison des pluies par des systèmes précipitants en V associés à la mousson. On observe ainsi une augmentation du nombre d'inondations rapportées depuis les années 2010, qui semble corrélée avec l'évolution de l'emprise urbaine de la ville. Les zones urbaines inondées de façon récurrente sont le plus souvent les quartiers « informels » construits directement en zones inondables et dont l'accroissement est important depuis les années 1990. L'étude des inondations du 2 et 3 août 2000 à Douala indique qu'on avait une situation synoptique propice à de fortes précipitations. On peut par l'exemple noter que l'humidité relative était presque de 99 %, ce qui implique que l'air est saturé en eau avec une chute de température. L'intérêt de cette étude est de réduire la vulnérabilité en intégrant les populations et les décideurs au coeur des stratégies de développement et de gestion urbaine des risques liés aux aléas climatiques. This article analyzes the temporal evolution of flooding in the urban area of Douala using methods allowing to compute a maximum flow value using meteorological data over a period of 35 years (1985-2019). A flood database is created using information from the press showing that Douala is frequently flooded during the rainy season by V-shaped precipitating systems associated to the monsoon. We can thus observe an increase in the number of floods reported since the 2010s, which seems to be correlated with the evolution of the city's urban footprint. The recurrently flooded urban areas are most often informal neighbourhoods built directly in flood-prone areas and whose increase has been significant since the 1990s. The case study of the floods of August 2 and 3, 2000 in Douala indicates that there was a synoptic situation conducive to heavy rainfall. On the other hand, relative humidity is almost 99 % which requires the air to be saturated with water with a drop in temperature, which will cause a change of state. The purpose of this study is to reduce vulnerability by integrating populations and decision-makers at the heart of development strategies and urban risk management related to climatic hazards.

scholarly journals The impact of GPS and high-resolution radiosonde nudging on the simulation of heavy precipitation during HyMeX IOP6

2021 ◽  
Author(s):  
Alberto Caldas-Alvarez ◽  
Samiro Khodayar ◽  
Peter Knippertz
Keyword(s):  
High Resolution ◽  
Temporal Resolution ◽  
Hydrological Cycle ◽  
Weather Prediction ◽  
Heavy Precipitation ◽  
Convective Precipitation ◽  
Small Scale ◽  
High Temporal Resolution ◽  
The Impact

Abstract. Heavy precipitation is one of the most devastating weather extremes in the western Mediterranean region. Our capacity to prevent negative impacts from such extreme events requires advancements in numerical weather prediction, data assimilation and new observation techniques. In this paper we investigate the impact of two state-of-the-art data sets with very high resolution, Global Positioning System-Zenith Total Delays (GPS-ZTD) with a 10 min temporal resolution and radiosondes with ~700 levels, on the representation of convective precipitation in nudging experiments. Specifically, we investigate whether the high temporal resolution, quality, and coverage of GPS-ZTDs can outweigh their lack of vertical information or if radiosonde profiles are more valuable despite their scarce coverage and low temporal resolution (24 h to 6 h). The study focuses on the Intensive Observation Period 6 (IOP6) of the Hydrological Cycle in the Mediterranean eXperiment (HyMeX; 24 September 2012). This event is selected due to its severity (100 mm/12 h), the availability of observations for nudging and validation, and the large observation impact found in preliminary sensitivity experiments. We systematically compare simulations performed with the COnsortium for Small scale MOdelling (COSMO) model assimilating GPS, high- and low vertical resolution radiosoundings in model resolutions of 7 km, 2.8 km and 500 m. The results show that the additional GPS and radiosonde observations cannot compensate errors in the model dynamics and physics. In this regard the reference COSMO runs have an atmospheric moisture wet bias prior to precipitation onset but a negative bias in rainfall, indicative of deficiencies in the numerics and physics, unable to convert the moisture excess into sufficient precipitation. Nudging GPS and high-resolution soundings corrects atmospheric humidity, but even further reduces total precipitation. This case study also demonstrates the potential impact of individual observations in highly unstable environments. We show that assimilating a low-resolution sounding from Nimes (southern France) while precipitation is taking place induces a 40 % increase in precipitation during the subsequent three hours. This precipitation increase is brought about by the moistening of the 700  hPa level (7.5 g kg−1) upstream of the main precipitating systems, reducing the entrainment of dry air above the boundary layer. The moist layer was missed by GPS observations and high-resolution soundings alike, pointing to the importance of profile information and timing. However, assimilating GPS was beneficial for simulating the temporal evolution of precipitation. Finally, regarding the scale dependency, no resolution is particularly sensitive to a specific observation type, however the 2.8 km run has overall better scores, possibly as this is the optimally tuned operational version of COSMO. In follow-up experiments the Icosahedral Nonhydrostatic Model (ICON) will be investigated for this case study to assert whether its numerical and physics updates, compared to its predecessor COSMO, are able to improve the quality of the simulations.

scholarly journals A Comparative Study Between Short Life- Cut off Low and Long Life-Cut off Low Accompanied by Heavy Precipitation Storms Over Iraq: Case Study

2020 ◽  
Vol 31 (2) ◽  
pp. 1
Author(s):  
HADIL JALIL ALSHOUHANI
Keyword(s):  
Comparative Study ◽  
Lower Troposphere ◽  
Heavy Precipitation ◽  
Short Life ◽  
Pressure System ◽  
Upper Troposphere ◽  
Isentropic Surface ◽  
Long Life ◽  
High Potential Vorticity

A comparative study between Short Life Cut Off Low (SL-COL) extended for one day, and Long Life Cut Off Low (LL-COL) extended for ten days associated with successive rain storms over Iraq on 21 to 30 April, 2018. The study tracking the evolution stages of both COLs in different pressure surfaces at troposphere layer, and found that there are many dynamical processes effect on prolong the life of COL. These processes exchanged their roles between different pressure levels. In both cases the high potential vorticity (PV) anomaly at 315ᵒ K isentropic surface is responsible on the emergence COLs, and the convection processes at lower troposphere and latent heat at upper troposphere are responsible on COLs dissipation. The main reasons of long-life COL can be summaries as a high-pressure system below COL at the surface which preventing the convection process, the formation of Omega block that promoting the COL system and preventing its dissipation rapidly in spite of the intense convection processes due to tropical moist system at the surface.

Sign in / Sign up

Export Citation Format

Share Document