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Although known as the warmest deserts of the world, rainfall and integrated water of Lut and Kavir Deserts is still unknown due to insufficient weather stations. The Dual-Frequency Precipitation Radar (DPR) onboard the Global Precipitation Measurement (GPM) mission satellite created an opportunity for use to study the rainfall and vertically integrated liquid water content (LWC) and integrated non-liquid (ice) water content (IWC) using statistical and distance analyses over the two deserts during winter months (December to March) of 2015–2020. The results showed good similarity between the GPM DPR and station data with a Pearson correlation coefficient of 0.81. March has the highest contribution in rain amount, which is about 37% in both deserts. March also has the largest contribution of the rainy days, being about 41.4 and 37.6% in the Lut and Kavir Deserts, respectively. LWC has the highest amount in the Lut Desert, while IWC is the largest in the Kavir Desert. Distance analysis showed that there is a significant increasing trend of rainfall from west to east in the Lut Desert. Elevation does not affect rainfall distribution strongly, but rainfall is highly influenced by the atmospheric-driven large-scale parameters. [ABSTRACT FROM AUTHOR]

Agriculture and hydrological management in western and northwestern Iran is highly sensitive to precipitation associated with Mediterranean and Sudanese cyclones particularly during spring and winter. Although many studies have focused on the theoretical basis of these cyclones, statistical analyses, especially with satellite observations, have not been undertaken. In this study, 40 cyclones during all months of 2015–2021 are characterized using data collected by Global Precipitation Measurement (GPM) dual‐frequency precipitation radar (DPR), Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) and ERA5 reanalysis within each cyclone quadrant. The results show that about 45% of cyclones have a lifetime between 1 and 2 days, and approximately 25% occur during April with a secondary peak in March (22.5%). Accordingly, cyclonic rainy days and rainfall amounts peak in April with values of 76.1% and 64.1%, respectively. The lowest (most negative) low‐ and mid‐tropospheric vertical velocity in the southeast and northeast quadrants indicates upward motion, which leads to the most intense latent heat release within the cyclone. Accordingly, the highest rainfall rates occur in the southeast and northeast quadrants, located within and ahead of the highest specific humidity quadrant (southeast) where the warm conveyor belt plays a significant role for rainfall formation. Maximum stratiform and convective rainfall rates are observed in the southwest and southeast quadrants, respectively. The distribution of rainfall rate is consistent with that of the storm‐top height pattern in all quadrants. The maximum percentage of warm rain to the total rain (34.6% on average) for both stratiform and convective precipitation falls in the southeast quadrant. The structure of these analysed cyclones is largely similar to that shown previously in the literature. According to the analysed rainfall in different life cycles, it is expected that the cyclones have the greatest impact (i.e., extreme rainfall) during the developing stage in the northeast and southeast quadrants, and during the mature stage in the southwest quadrant. The lowest influence is during the dissipating stage. The results from this study can help decision makers within the hydrological and risk management industries. [ABSTRACT FROM AUTHOR]

Since silver nanoparticles (AgNPs) are used as nanofungicides and nanopesticides in agriculture, the toxicity of AgNPs as well as AgNO3 must be determined. Besides this, we evaluated the combined effects of salicylic acid (SA) and nitric oxide (NO) on responses of Phlomis tuberosa plants to Ag-induced stress. The results of growth parameters together with measurement of malondialdehyde (MDA) indicated that exposure to 1000 mg L-1 of AgNPs or AgNO3 exerted more toxicity, which was closely associated with the over-accumulation of ROS and the reduction of photochemical functioning. However, SNP (NO) and SA addition successfully alleviated adverse impact of AgNPs on Phlomis seedlings. Maximum amelioration of Ag-induced stress was found by combined treatments of SA+NO. Phlomis plants primed with SA+NO exhibited higher synthesis of chlorophyll b and carotenoid pigments to ameliorate AgNP-induced adverse effects on chlorophyll fluorescence parameters. SA+NO led to high levels of proline under both AgNPs and AgNO3 treatments. A further increase in antioxidants (phenolic compounds) was observed in NO-primed plants under AgNPsinduced stress, which was attendant with the high level of CAT and APX activities. Increase in total Ag translocation into shoot organs and cell survival were also enhanced by SA+NO under AgNPs stress. We concluded that SA+NO mitigated the inhibitory effects of AgNPs stress on the photosynthetic apparatus by increasing the phenolic compounds and carotenoids as well as by regulating accumulation of Ag, ROS and antioxidants. The present findings provide important knowledge to design strategies that minimize the negative impact of AgNPs and AgNO3 on crops. [ABSTRACT FROM AUTHOR]

To answer the question "what has changed the surface temperatures of water bodies around Iran under climate change conditions," Moderate Resolution Imaging Spectroradiometer (MODIS) sea surface temperature (SST) data with 9.2-km spatial resolution and monthly time step were evaluated. A significant increasing trend was obtained using Pearson's correlation coefficient and Mann-Kendall trend test on data from the Caspian Sea (June) and the Southern Gulfs (September). High correlations of 0.69 and 0.97 between remotely sensed data and ERA-Interim reanalysis data were also obtained for June and September, respectively. To assess the impact of some climatic parameters on SST variability in those two months, zonal and meridional wind at 10 m, wind speed at 10 m, air temperature at 2 m, and mean sea level pressure were evaluated. High correlations between meridional wind and the Southern Gulf SST, and meridional wind and Caspian SST were −0.86 and 0.75, respectively. Moreover, the results showed an important role of air temperature (0.96) and sea level pressure (−0.77) in the rising temperature trends of the Southern Gulfs. Wind speed was also detected in both regions as a booster of the trend. [ABSTRACT FROM AUTHOR]