The Rainfall Seasonality Index() is used to study the spatial and temporal change in rainfall behavior in that contribute in improvement of water and management plans of water resources systems and agriculture in a certain region especially during dry seasons. Rainfall date is obtained for twenty-eight weather stations in Iraq to find the seasonality index for each station.To give a clear conception of rainfall regime, the study area is divided to three zone according to amount rainfall. The results described the rainfall regime and showed that of study area

Extreme rainfall is one of the environmental hazards with disastrous effects on the human environment. Water resources management is very vulnerable to any changes in rainfall intensities. A spatiotemporal analysis is essential for study the impact of climate change and variability on extreme rainfall. In this study, daily rainfall data for 36 meteorological stations in Iraq during 1981–2017 were used to investigate the spatiotemporal pattern of 10 extreme rainfall indices using RClimDex package. These indices were classified into two categories: rainfall total (PRCPTOT, SDII, R95p, R99p, RX1day, and RX5day) and rainfall days (CDD, CWD, R10, and R20). Depending on the mean annual precipitation data, the study area was divided into three climatic zones to examine the time series features of those 10 indices. Results showed a tendency to increase in precipitation toward the northwestern part of Iraq, and more than 70% of stations achieved a positive trend for most indices. The most frequent negative trend appeared in eight stations distributed in the western and southern parts of Iraq, namely (Heet, Haditha, Anah, Rutba, Qaim, Nukheb, Najaf, and Fao). A significant positive trend appeared obviously in PRCPTOT and R95p with a rate of 0.1–4.6 and 0.5–2.7 mm per year, respectively. Additionally, the least trend increasing appeared in all precipitation days indices specifically in R10 and R20. Time series analyses revealed a positive trend in all regions under study, except SDII in the southern region. The most significant rate of change was noticed in regions one and two (northern and middle parts of Iraq), particularly for PRCPTOT and R95p 3.26 and 2.45 mm per day, respectively. Only the northern and eastern regions of Iraq experienced a high probability of significant extreme rainfall.

The erosivity factor have a major effect on soil therefor a lot off researchers are interested about it. Actually, the erosivity depend on rainfall that could be a main source to water which effect on soil. To understand the erosivity factor in Iraq, we attempt to explain erosivity factor throughout 30 years (1980– –2010). Because of daily data of interval 15 and 30 min are not provided in this area, we used the Fournier modifi ed index (MFI) that based on monthly date of rainfall. Also, we applied linear regression equation between annual rainfall and the MFI to predict the variables and coeff cient of determination was calculated. The study period divided to three decades and spatial distribution by Kriging method was used to interpolate the MFI of study area which calculate by ArcGIS 10.4.1. The results show that in the northern zone of Iraq MFI maximum values were recorded and in the range of MFI above 160. Moreover, in Emadiyah station the MFI excessed 250, which means the erosivity factor has a big effect on soil in this zone. Whereas, in middle zone, the MFI has range 0–120 but most of years of study period recorded 0–90 of the MFI. In southern zone, the MFI was 0–60 therefore the erosivity factor was moderated or law. The linear regression models were found for each station of study area and only Emadiyah, Teleafer, Khanqin and Nasiriya have weak coefficient determination.

No abstract

<p>Heat waves lead to increased mortality due to heat exhaustion and heatstroke, wildfire, reduced agricultural yields, increased energy demand, economic predicaments and other societal issues. Heat wave events over the Middle-East have received far less attention compared to events elsewhere. Here, we provide a comprehensive characterization of heat wave events over Iraq, covering the period 1980-2019.<br />We use ERA5 reanalysis data for Northern summer (June-July-August) to identify heat waves in daily maximum 2-m temperature (Tmax) data and study them using composite analyses and clustering. We define a heat wave event if the Tmax anomaly exceeds the 90th percentile over three consecutive days, provided this threshold exceedance covers at least 50% of our target area.</p> <p>The composite-mean evolution of daily Tmax anomalies demonstrates that our heat waves typically strengthen gradually over the week preceding the central day with a sharp decline in strength at positive lags, reaching an average maximum anomaly of ~3.7 K at the central day. We find the heat waves to extend from the Arabian peninsula northward across Iraq toward southwestern Russia. Clustering of all heat wave events reveals two dominant flow anomaly patterns that roughly distinguish early from late summer events.</p> <p>The first cluster (early summer events) is associated with anomalous anticyclonic flow associated with a quasi-stationary upper-level high pressure system to the north-east of Iraq precisely over Caspian sea. This anomalous anticyclonic flow is embedded in a Rossby wave train that initially propagates along the north Atlantic wave-guide, then further equatorward along the North African-Asian jet just before the central day. Our composite-mean evolution for this first cluster further shows mid-tropospheric subsidence over the Zagros mountains, i.e., upstream of our heat wave target area. Downslope Foehn winds appear to enhance the heat wave over Iraq.</p> <p>In contrast, the second cluster is primarily composed of late-summer events and shows strong anomalies in the Shamal winds - a pronounced low-level north-westerly jet along the western edge of the Zagros mountains. During these late summer heat wave events the Shamal jet is substantially weakened or even reversed, transporting warm air from the Persian gulf into the target region. </p> <p> </p>