Coast Mountains Research Articles

Deep Learning for Bias Correction of Satellite Retrievals of Orographic Precipitation

The performance of various composite satellite precipitation products is severely limited by their individual passive microwave (PMW)-based retrieval uncertainties because the PMW sensors have difficulties in resolving heavy rain and/or shallow orographic precipitation systems. Characterizing the error structure of PMW retrievals is crucial to improving precipitation mapping at different space–time scales. To this end, this article introduces a machine learning framework to quantify the uncertainties associated with satellite precipitation products with an emphasis on orographic precipitation. A deep convolutional neural network (CNN) is designed, which utilizes the ground-based Stage IV precipitation estimates as target labels in the training phase, to reduce biases involved in the precipitation product derived using the NOAA/Climate Prediction Center morphing technique (CMORPH). The products before and after bias correction are evaluated using four independent precipitation events over the coastal mountain region in the western United States, and the impact of topography on satellite-based precipitation retrievals is quantified. Experimental results show that the orographic gradients have a strong impact on precipitation retrievals in complex terrain regions. The accuracy of CMORPH is dramatically enhanced after applying the proposed machine learning-based bias correction technique. Using Stage IV data as references, the overall correlation (CC), normalized mean error (NME), and normalized mean absolute error (NMAE) of CMORPH are improved from 0.55, 32%, 63%, to 0.88, −2%, 39%, respectively, after bias correction for the independent case studies presented in this article. Such a machine learning scheme also has great potential for improved fusion of other or future satellite precipitation retrievals.

Variation in age of primiparity in mountain goats (Oreamnos americanus) estimated from horn growth increments

Variation in age of primiparity is important for population dynamics and wildlife management because it can affect population growth. Using a novel technique based on the trade-off between annual horn growth and reproduction, we estimated the age of primiparity for 2274 female mountain goats (Oreamnos americanus (Blainville, 1816)) harvested across British Columbia, Canada, from 1976 to 2019. We then investigated spatio-temporal variation in the probability that harvested females were primiparous when aged 3, 4, or 5 years and older using Bayesian ordinal regressions. We found that the probability of primiparity at 3 years decreased over time in nearly all mountain ranges. In the Coastal Mountain range, however, the probability of primiparity at age 3 significantly increased. These results suggest that the large coastal populations of mountain goats could be more resilient to harvest than other populations in British Columbia, which may be experiencing environmental effects promoting later primiparity. Models predicting age of primiparity from annual growth measures are a valuable tool for wildlife management and could help conservation of many species.

Summer Season Precipitation Biases in 4 km WRF Forecasts Over Southern China: Diagnoses of the Causes of Biases

AbstractIn a recent study, we evaluated the performance of real‐time convection‐permitting WRF model forecasting over China. Although the overall rainfall distribution and diurnal cycle are well simulated, the model greatly overestimates the rainfall intensity in southern China and the predicted rainfall shows a southeast location bias. In this study, possible factors contributing to the precipitation forecast bias are discussed. The precipitation over southern China is found to be greatly influenced by land‐sea circulations. While the model captures diurnal variations of winds well, the predicted amplitude and onset timing of the land/sea breezes differ from observations. Cold bias of land‐surface temperature is shown to partially cause wind bias. In the afternoon, the cold bias results in a weakened inland penetration of sea breeze, which in turn leads to more rain on the eastern south‐China coastline. During nighttime, excessive cooling over land results in a stronger land breeze, leading to location bias of early morning precipitation. While the observed coastal rain belt is mostly located over land during early morning, the predicted coastal rain belt is mostly located over ocean. In addition, the model overestimates moisture at low levels, especially over the southern slope of the coastal mountains and over ocean, which explains the excessive rainfall over southern China. This study emphasizes the importance of accurately simulating land‐surface‐related variables for precipitation forecast in coastal regions where land‐sea contrast plays an important role.

1206. Effects of Climatic Variability on Lyme Disease Outbreaks in California

BackgroundClimate change has increased the risk of tick borne infections. The life cycle and prevalence of deer ticks are strongly influenced by temperature. Warmer temperatures associated with climate change are projected to increase the range of suitable tick habitats driving the spread of Lyme disease (LD). Short winters could also increase tick activity increasing the risk of exposure. This study examines the relationship between LD incidence and temperature-precipitation and their anomalies in CA counties.MethodsTrends and relationships of Lyme Disease (LD) cases and climatic factors were analyzed among the California counties from 2000 to 2019. Lyme disease tabulate data and climatic data were obtained from Centers for Disease Control, and NOAA, and Climate Data Guide respectively. Canonical correspondence analysis (CCA) was performed using variables: (i) LD cases, (ii) precipitation & anomaly, and temperature & anomaly. The CCA ordination explained the variability between LD cases and climatic variables. Biplots were used to visualize the associations between LD cases and climatic anomalies.ResultsWe compared the countywide LD cases in relation to climatic factors in California from 2000 to 2019. A total of 96 cases in 2000, 117 cases in 2009, and 144 cases in 2019 were reported in the 55 counties of California. Santa Clara reported the highest LD cases in 2003 (23 cases; 16%), followed by Los Angeles in 2013 (20 cases; 18%) and Santa Cruz in 2017 (19 cases; 13%). CCA ordination showed distinguishable clustering patterns between southern California counties (Santa Clara, Santa Cruz, Alameda, and San Diego) and northern coast and Klamath mountains range (Humboldt, Trinity, Shasta, and Siskiyou) regions (Fig. 1). Moderate mean annual temperature (56.5 °F - 62.5 °F) and temperature anomaly (3.8 °F - 5.5 °F) were the most important variable predictor for high LD outbreak. The CCA ordination shows the relationships between Lyme Disease and climatic variables for the 55 Counties of California. The bottom right circle represents Lyme cases positively correlated with temperature anomaly (3.8 °F - 5.5 °F) and moderate annual mean temperature (56.5 °F - 62.5 °F). The upper left circle represents Lyme cases negatively correlated with mean annual precipitation.ConclusionModerate temperature with low moist spell anomalies in the south neighboring CA counties showed a positive influence on LD outbreak. The climatic conditions in those areas suitable for Oak trees and masting acorn resulting in the establishment of tick and host (deer) populations. We recommend robust surveillance and lab testing for patients with a history of tick bites in these regions.Disclosures All Authors: No reported disclosures

Growth and yield of pomato under the Syrian coastal mountains conditions

Abstract. The world has always been striving to increase and intensify agricultural production, and there are several attempts to acheive that, such as grafting tomato on potato to obtain two crops from one plant. This investigation was conducted during 2020 in open field in Nahl village, Baniyas, Tartous Governorate, Syria. The vegetative and generative growth and yield have been studied for pomato (grafted tomato on potato) and compared to each tomato and potato separately. Tomato plants were significantly superior in plant height to pomato plants after 23 days of planting until the end of the experiment. On the other hand, there were significant differences between tomato plants and pomato plants in the leaf area after 23, 51 and 65 days of planting. Also, tomato plants significantly outperformed pomato plants in the number of flowers and fruits per plant and the tomato fruit set percent. Anyway, tomato plants were significantly superior in the average yield of tomato fruits per plant (1657 g.plant-1) to pomato plants (185 g.plant-1), while there were insignificant differences in the average yield of potato tubers per plant between pomato which failed to produce tubers and potato (48.25 g.plant-1). Studying the tomato fruit fresh weight showed a significant superiority of tomato plants (54.37 g.fruit-1) to pomato plants (35.97 g.fruit-1), while there were insignificant differences in the other physical (tomato fruit height, diameter and shape index) and chemical (tomato fruit content of total acids, total soluble solids and dry matter, %) properties.

Forecast Skill for California Heavy Precipitation Periods from the High-Resolution Rapid Refresh Model and the Coupled Ocean–Atmosphere Mesoscale Prediction System

Abstract Precipitation forecasts from the High-Resolution Rapid Refresh model (HRRR) of the National Centers for Environmental Prediction (NCEP) and the Navy’s Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) are examined during heavy precipitation periods in California. Precipitation forecast discrepancies between the two models are examined during a recent heavy winter precipitation episode in California from 6 to 8 December 2019. The skill of initial 12-h precipitation forecasts is examined objectively from 1 December 2018 to 28 February 2019 from the HRRR, COAMPS, and NCEP’s North American Mesoscale Forecast System (NAM-3km). The HRRR exhibited lower seasonal biases and higher skill based on several metrics applied to a sample of 48 12-h periods during California’s second wettest winter season during the past 20 years. Overall, the NAM-3km and COAMPS exhibited a large wet bias over the interior mountain regions while the HRRR model indicated a dry bias along the northern coastal region. All models tended to underestimate precipitation along the coastal mountains of Northern California. To highlight the regional and localized nature of forecast skill, the fraction skill score (FSS) metric is applied across ranges of spatial scales and precipitation values. For the domain as a whole, the HRRR had higher precipitation forecast skill compared to the other two models, particularly within radial distances of 20–30 km and moderate (10–50 mm) precipitation totals. FSS computed locally highlights the HRRR’s overall higher skill as well as enhanced skill in the southern half of the state.

A terminal distribution network black-start optimization method based on pruning algorithm considering distributed generators

The main objective of the black-start in a terminal distribution network is restoring the regional distribution network in a blackout. Aiming at the problem that there are multiple optimization objectives in the process of black start, a black start model with comprehensive consideration is established, considering the minimum switching operation cost, maximum recovery efficiency and priority start of important load. Then, the constraints of voltage and frequency stability of the distribution network in black-start are put forward. Aiming at the problem that heuristic algorithm such as binary particle swarm optimization cannot get the global optimal solution, a black-start method based on pruning algorithm is proposed, which has higher efficiency than traditional algorithm as well as the ability to search the global optimal method. Finally, the efficiency of the above method is verified in the terminal distribution network of a coastal mountain county.

Spatial assessment of drought features over different climates and seasons across Iran

Drought is one of the most complex phenomena in the world; so, proper management is very important in monitoring and reducing its damage. For this purpose, Standard Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and Reconnaissance Drought Index (RDI) indices were used to analyze the intensity and frequency of drought in the coastal wet, mountain, semi-mountain, semi-desert, desert, and coastal desert climates of Iran in four seasons, separately: autumn, winter, spring, and summer. Forty-three synoptic stations with a common statistical period of 50 years (1969–2019) were selected. The results showed that the trend of drought in winter and summer is increasing in all studied climates. The comparison of the results in the trend analysis of the drought showed the same trend, but the SPEI index compared to the other indicators showed a quicker response to changes in drier climates. The highest correlation (0.80–0.99) between SPI-RDI and SPEI-RDI indices in coastal desert, mountain, and semi-mountain climates and the lowest correlation (0.34) between SPI-SPEI and SPEI-RDI indices in semi-desert, desert, and coastal desert climates were obtained. SPI-RDI variations showed similar values in colder climates. The SPEI is based on precipitation and temperature data, and it has the advantage of combining multi-scalar character with the capacity to include the effects of temperature variability in the drought assessment. Thus, SPEI is recommended as a suitable index for studying and identifying the effect of climate change on drought conditions.

Tandem dating methods constrain late Holocene glacier advances, southern Coast Mountains, British Columbia

Combined use of radiocarbon-dated subfossil wood within lateral moraines and surface exposure ages on moraine boulders provides an approach to better constrain times of glacier advance and onset of retreat. We test this method at Gilbert Glacier in the southern Coast Mountains of British Columbia where units of sediments associated with glacier expansion date to 4.8–4.6, 4.5–4.3, 4.0–3.9, 3.8–3.6, 3.4, 3.2–2.9, 2.7, and 0.5–0.3 kilo calendar years BP (ka; 2-sigma age range). Surface exposure (10Be) ages reveal times of moraine stabilization at 1.83–1.78, 1.38–1.28, 0.85–0.76, and 0.13–0.06 ka (interquartile range). Analysis of both datasets, as well as previously published regional advance records, narrows the age range of four late Holocene advances to 2.0–1.8, ∼1.5–1.3, ∼0.9–0.8, and 0.4–0.1 ka. We advocate for widespread use of our tandem approach at other sites throughout Earth's high mountains to narrow the uncertainties associated with glacier expansion and better understand how glaciers respond to climate change.

Assessing fog water collection in the coastal mountain range of Antofagasta, Chile

Fog water collection can be an alternative source of water supply in areas with limited water resources. Fog water is usually collected with plastic meshes mounted on wooden or metal frames arranged perpendicular to winds carrying fog. This study assessed fog water collection at the coastal mountain range of Antofagasta, Chile, with the purpose of analyzing the relationship between collected water and local meteorological conditions. For this, four standard 1-m2 fog collectors with meteorological instrumentation were located at different places in the study area. From August 2019 to February 2020, the collectors recorded data on collected water and atmospheric variables, including wind speed, wind direction, relative humidity, and ambient temperature. The results indicate that fog water collection ranged between 0.16 ± 0.02 and 0.37 ± 0.05 L m−2 day−1 averaged over the entire period. The collection was notably reduced in summer, with values generally <0.09 L m−2 day−1, due to fewer days with fog collection events. More than half of the collected water was obtained in less than 8% of the study days. The frequency of foggy days and orientation of the collectors were among the main factors explaining the differences in yield between the collectors.

Retraction Note: Coastal mountain landscape and urban plant planning based on remote sensing imaging

Retraction Note: Coastal mountain landscape and urban plant planning based on remote sensing imaging

Detrital zircons record the evolution of the Cathaysian Coastal Mountains along the South China margin

AbstractThe Cathaysian Coastal Mountains are thought to be an ancient high‐topographic feature that existed along the margin of South China. They are characterised by extensive Jurassic–Cretaceous magmatism; however, their formation mechanism and timing remains uncertain. In this paper, we present sedimentological and detrital zircon analyses from Cretaceous–Eocene strata and drainage sediments from Hainan Island. Our analyses show a change in provenance from a proximal Cathaysian Coastal arc source in Cretaceous strata to a widely distributed intra‐island granite source in the Eocene strata and modern river sediments. Reconstruction of the crustal thickness evolution for the South China margin from Eu/Eu*‐in‐zircon proxy shows significant crustal thickening during the Late Jurassic–Cretaceous, thereby suggesting the existence of the Cathaysian Coastal Mountains. Together with a compilation of detrital zircon U‐Pb ages in the northern basins of the South China Sea margin, we conclude that the Cathaysian Coastal Mountains extended from the Red River region to Taiwan along the South China margin during the Late Jurassic–Cretaceous and then collapsed/eroded from northeast to southwest during the Eocene–Miocene. This large mountain range supplied detrital sediments to the marginal basins in the northern South China Sea and formed a topographic barrier that prohibited moist Pacific air to reach the relatively arid inland area of South China during the Late Jurassic–Cretaceous.

The tempo and conditions of metamorphism during magmatism, southern Coast Mountains batholith, British Columbia, Canada

AbstractGarnet Sm‐Nd ages and pressure–temperature–time (P–T–t) paths for pelitic and semipelitic metamorphic rocks in the Mount Waddington area constrain the relationship between metamorphism and high‐flux magmatism recently identified in the southern Coast Mountains batholith. Amphibolite facies metamorphism in this area occurred at 99–90, 80, and 72–65 Ma at varying conditions of ~3 to 8 kbar and ~450°C to 685°C, partly associated with high magmatic fluxes at 85–70 and 61–48 Ma. P–T–t paths indicate increases in pressure and temperature of 2 kbar and 120°C at c. 80 Ma and up to 3 kbar and 165°C at 72–65 Ma. Garnet growth at c. 72 and 80 Ma was synchronous with a high‐flux event at 85–70 Ma. However, c. 65‐, 90‐, and 99‐Ma garnet growth cannot be directly attributed to nearby plutons and occurred during lulls between high magmatic flux events. The simplest explanation for the observed P–T–t paths for metamorphism is a single regional‐scale event between 99 and 64 Ma, synchronous with and in response to crustal contraction. Rock textures and pressure–temperature (P–T) isochemical phase diagrams indicate that most sampled rocks reached near‐solidus conditions with little or no melting. Although partial melting of sedimentary rocks has been proposed to contribute toward high‐flux magmatism in the northern and central Coast Mountains, the timing of metamorphism and high‐flux events differs in the Waddington area, suggesting that they are unrelated. Therefore, we conclude that metamorphism and partial melting of rocks exposed at the current level of exhumation played little or no role in construction of the batholith in the Waddington–Raleigh area of the southern Coast Mountains batholith.

Calceolariaflavida (Calceolariaceae) a new endemic species to central Chile.

A new species of Calceolariasect.Cheiloncos endemic to central Chile is described. A comparison with the morphologically similar species Calceolariaasperula and Calceolariapetioalaris is made, and a key as well as detailed images to differentiate them is provided. The species is only known from the Natural Sanctuary Cerro El Roble, which is part of the coastal mountain range of central Chile and can be considered as Critically Endangered (CR) under the IUCN categories and criteria.

Altitude of the East Asian Coastal Mountains and Their Influence on Asian Climate During Early Late Cretaceous

AbstractThe East Asian coastal mountains have been in place during the Late Cretaceous times, thus substantially influencing the Asian climate. So far, their altitude is uncertain. Here we investigate the influence of such mountains on Asian climate using an atmosphere‐ocean general circulation model, Community Earth System Model version 1.2.2. Simulation results show that extensive deserts would develop over the eastern part of the East Asia if the altitude of the coastal mountains was greater than 2 km. This is due to the pumping effect of the coastal mountains which deprives the moisture from the East Asian interior during summer and autumn, leading to less precipitation and greater potential evapotranspiration. The existence of extensive desert areas would be more consistent with the presented Asian paleoenvironmental reconstructions. Therefore, our results independently indicate that the altitude of the coastal mountains had attained 2 km or more by the early Late Cretaceous.

Testing local and extraregional sediment sources for the Late Cretaceous northern Nanaimo basin, British Columbia, using 40Ar/39Ar detrital K-feldspar thermochronology

Abstract Detrital K-feldspar 40Ar/39Ar thermochronology was conducted on clastic sedimentary rock samples collected from northern exposures of the Upper Cretaceous Nanaimo Group on Vancouver Island and adjacent Gulf Islands of British Columbia to constrain the denudation history of the local Coast Mountains batholith source region and determine the origin of extraregional sediment supplied to the basin. Strata of the northern Nanaimo Group deposited between 86 and 83 Ma (Comox and Extension formations) exhibit a 130–85 Ma age distribution of detrital K-feldspar 40Ar/39Ar ages that lack age maxima. These are interpreted to have been sourced from the southwestern Coast Mountains batholith. Younger strata deposited between 83 and 72 Ma (Cedar District and De Courcy formations) yield a broader age range (150–85 Ma) with an age maximum near the depositional age. These results indicate focused denudation of deeper-seated rocks east of the Harrison Lake fault. The youngest units deposited after 72 Ma (Geoffrey, Spray, and Gabriola formations) primarily yield younger than 75 Ma detrital K-feldspar ages with pronounced age maxima near the depositional age. This sediment was sourced extraregionally relative to the Coast Mountains batholith. We sought to constrain the origin of the extraregional sediment by measuring the thermal histories of 74 samples of basement rocks from throughout the Pacific Northwest, and by compiling a database of over 2400 biotite 40Ar/39Ar and K/Ar cooling ages from predominantly Cretaceous batholiths along the western North American margin. This analysis focused upon two previously proposed source regions: the Idaho batholith and the Mojave-Salina margin of southern California. The Nanaimo detrital K-feldspar 40Ar/39Ar age distributions favor the peraluminous Late Cretaceous Idaho batholith and its Proterozoic Belt-Purcell Supergroup sedimentary wall rock as the more likely source of the extraregional sediment and disfavor the Baja–British Columbia hypothesis for 2000–4000-km-scale translation of rocks along the margin during the Late Cretaceous.

Evolution of the Late Cretaceous Nanaimo Basin, British Columbia, Canada: Definitive provenance links to northern latitudes

AbstractAccurate reconstruction of the Late Cretaceous paleogeography and tectonic evolution of the western North American Cordilleran margin is required to resolve the long-standing debate over proposed large-scale, orogen-parallel terrane translation. The Nanaimo Basin (British Columbia, Canada) contains a high-fidelity record of orogenic exhumation and basin subsidence in the southwestern Canadian Cordillera that constrains the tectonic evolution of the region. Integration of detrital zircon U-Pb geochronology, conglomerate clast U-Pb geochronology, detrital muscovite 40Ar/39Ar thermochronology, and Lu-Hf isotopic analysis of detrital zircon defines a multidisciplinary provenance signature that provides a definitive linkage with sediment source regions north of the Sierra Nevada arc system (western United States).Analysis of spatial and temporal provenance variations within Nanaimo Group strata documents a bimodal sediment supply with a local source derived from the adjacent magmatic arc in the southern Coast Mountains batholith and an extra-regional source from the Mesoproterozoic Belt Supergroup and the Late Cretaceous Atlanta lobe of the Idaho batholith. Particularly robust linkages include: (1) juvenile (εHf &amp;gt;+10) Late Cretaceous zircon derived from the southern Coast Mountains batholith; (2) a bimodal Proterozoic detrital zircon signature consistent with derivation from Belt Supergroup (1700–1720 Ma) and ca. 1380 Ma plutonic rocks intruding the Lemhi subbasin of central Idaho (northwestern United States); (3) quartzite clasts that are statistical matches for Mesoproterozoic and Cambrian strata in Montana and Idaho (northwestern United States) and southern British Columbia; and (4) syndepositional evolved (εHf &amp;gt;−10) Late Cretaceous zircon and muscovite derived from the Atlanta lobe of the Idaho batholith. These provenance constraints support a tectonic restoration of the Nanaimo Basin, the southern Coast Mountains batholith, and Wrangellia to a position outboard of the Idaho batholith in Late Cretaceous time, consistent with proposed minimal- fault- offset models (&amp;lt;~1000 km).

Giant meandering channel evolution, Campos deep-water salt basin, Brazil

AbstractSubmarine channels are conduits for sediment delivery to continental margins, and channel deposits can be sandy components of the fill in tectonically active salt basins. Examples of salt-withdrawal basin fill commonly show successions of sandy channelized or sheet-like systems alternating with more mud-rich mass-transport complexes and hemipelagites. This alternation of depositional styles is controlled by subsidence and sediment-supply histories. Salt-basin fill comprising successions of largely uninterrupted meandering-channel deposition are less commonly recognized. This begs the questions: can sediment supply be large enough to overwhelm basin subsidence and result in a thick succession of channel deposits, and, if so, how would such a channel system evolve? Here, we use three-dimensional seismic-reflection data from a &amp;gt;1500 km2 region with salt-influenced topography in the Campos Basin, offshore Brazil, to evaluate the influence of salt diapirs on an Upper Cretaceous–Paleogene giant meandering submarine-channel system (channel elements &amp;gt;1 km wide; meander wavelengths several kilometers to &amp;gt;10 km). The large scale of the channels in the Campos Basin suggests that sediment discharge was large enough to sustain the meandering channel system in spite of large variability in subsidence across the region. We interpreted 22 channel centerlines to reconstruct the detailed kinematic evolution of this depositional system; this level of detail is akin to that of recent studies of meandering fluvial channels in time-lapse Landsat satellite images. The oldest channel elements are farther from salt diapirs than many of the younger ones; the centerlines of the older channel elements exhibit a correlation between curvature and migration rate, and a spatial delay between locations of peak curvature and maximum migration distance, similar to that observed in rivers. As many of the younger channel centerlines expanded toward nearby salt diapirs, their migration pattern switched to downstream translation as a result of partial confinement. Channel segments that docked against salt diapirs became less mobile, and, as a result, they do not show a correlation between curvature and migration rate. The channel migration pattern in the Campos Basin is different compared to that of a tectonically quiescent continental rise where meander evolution is unobstructed. This style of channelized basin filling is different from that of many existing examples of salt-withdrawal minibasins that are dominated by overall less-channelized deposits. This difference might be a result of the delivery of voluminous coarse sediment and high discharge of channel-forming turbidity currents to the Campos Basin from rivers draining actively uplifting coastal mountains of southeastern Brazil. Detailed kinematic analysis of such well-preserved channels can be used to reconstruct the impact of structural deformation on basin fill.

Interpretation of the Geological Romance of Kendari Bay Using Landsat 5 TM

Kendari Bay is part of Kendari City. Kendari Bay is a city landmark in addition to its economic and environmental functions.. The condition of Kendari Bay is experiencing a fairly high sedimentation problem, so that it begins to cause problems with land availability and space utilization patterns in the Kendari Bay area. The endogenous process of dynamic earth activities is a part that needs to be considered in managing that problems. This study aims the geological conditions of Kendari Bay by using remote sensing as a form of studying the geological conditions of Kendari Bay. Using Landsat 5 TM imagery in 1990, it was used to see the natural geological conditions of Kendari Bay, using the false color composite method and interpretation of photo images visually and validated through field observations. Landsat image processing and interpretation using Quantum GIS, resulted in Kendari bay can be divided into several physiography, namely coastal zone, estuary zone, fluvial zone, plain zone, hill zone, and mountain zone (Head land). The physiography can be seen from the geological characteristics such as the lithology which is composed of alluvial deposits to limestone. The results of interpretation of composite color images and validation of direct observation data in the field show a qualitative suitability.

Characteristics of Deep Convective Systems and Initiation during Warm Seasons over China and Its Vicinity

The spatiotemporal statistical characteristics of warm-season deep convective systems, particularly deep convective systems initiation (DCSI), over China and its vicinity are investigated using Himawari-8 geostationary satellite measurements collected during April-September from 2016 to 2020. Based on a satellite brightness temperature multiple-threshold convection identification and tracking method, a total of 47593 deep convective systems with lifetimes of at least 3 h were identified in the region. There are three outstanding local maxima in the region, located in the southwestern, central and eastern Tibetan Plateau and Yunnan-Guizhou Plateau, followed by a region of high convective activities in South China. Most convective systems are developed over the Tibetan Plateau, predominantly eastward-moving, while those developed in Yunnan-Guizhou Plateau and South China mostly move westward and southwestward. The DSCI occurrences become extremely active after the onset of the summer monsoon and tend to reach a maximum in July and August, with a diurnal peak at 11–13 LST in response to the enhanced solar heating and monsoon flows. Several DCSI hotspots are identified in the regions of inland mountains, tropical islands and coastal mountains during daytime, but in basins, plains and coastal areas during nighttime. DCSI over land and oceans exhibits significantly different sub-seasonal and diurnal variations. Oceanic DCSI has an ambiguous diurnal variation, although its sub-seasonal variation is similar to that over land. It is demonstrated that the high spatiotemporal resolution satellite dataset provides rich information for understanding the convective systems over China and vicinity, particularly the complex terrain and oceans where radar observations are sparse or none, which will help to improve the convective systems and initiation nowcasting.