Ecohydrology in water-limited environment using quantitative remote sensing - the Heihe River basin (China) case

Water-limited environments exist on all continents of the globe and they cover more than 30% of the Earth’s land surface. The eco-environments of these regions tend to be fragile and they are changing in a dramatic way through processes like land desertification, shrinking of oases, groundwater depletion, and soil erosion. These are either human induced or results of a changing climate. Implications of these changes for both the regional hydrologic cycle and the vegetation have been documented. Since these changes occur over a wide range of scales in space and time, remote sensing methods are needed to monitor the land surface characteristics, to observe changes in vegetation and hydrological states, and to compare these with predictions from hydrological models. It is widely accepted that remote sensing methods offer the ability to acquire spatially continuous measurements over large areas. Remote sensing can also help to visualize complex processes because the spatial data can be captured regularly over time. China is one of several countries with large arid and semi-arid areas. The Heihe River basin, situated in the arid inland of northwestern China, is one of the areas severely affected by ecoenvironmental degradation and recovery. The problem of the degraded environment is due to overexploitation of surface and ground water leading to shrinking of oases, including the decline and death of natural vegetation, and the lowering of the groundwater table. Exhaustive (over-)use of water resources is the main cause of land degradation in the lower reaches of the basin, called the Ejina oasis. The whole Heihe River basin is therefore selected as study area in this thesis to analyze the long-term eco-environmental changes. What happens in this river basin is likely to have a growing influence on regional hydrological cycles, even affecting human life. Effective management of eco-environmental problems in this critical zone of water-limited conditions will provide scientific evidence for protecting and improving the eco-environment in these Chinese northwestern arid regions, eventually resulting in land improvement. Studies on quantifying the relationship between the vegetation and the water resources are a critical step in developing an ecohydrological approach to resources management in order to minimize environmental degradation. Remote sensing measurements can help us to better understand the effects of changes in water management on hydrological processes and their subsequent feedback to the eco-environment at the regional scale. Remote sensing methods can also provide information to quantify heterogeneity and change at a large scale. Therefore, the main objective of this thesis is to develop a methodology for the quantitative assessment of eco-environmental changes at a large scale in arid regions by integrating remote sensing methods in ecohydrological approaches. Chapter 1 outlines the significance of quantitative assessment of eco-environmental changes using remote sensing methods and applying them for ecohydrology in northwestern China, resulting in the specific research objectives of this thesis. Chapter 2 quantifies both the vertical and horizontal distribution of vegetation in the Qilian Mountains area, representing the upper reaches of the Heihe River basin, based on MODIS NDVI images from the year 2000 - 2006. Our analysis reveals that elevation and aspect are two important impact factors for the vertical distribution of vegetation in a mountainous area. The NDVI increases with the elevation and reaches a maximum value at a certain elevation threshold, and then decreases as the elevation increases beyond this threshold. The optimal vegetation growth is on the shady side of the mountains because of less evapotranspiration. The best combination of temperature and precipitation is assessed providing good conditions for vegetation growth. Chapter 3 presents an efficient method to estimate the regional annual evapotranspiration (ET) based on the SEBS algorithm (Surface Energy Balance System) in the Zhangye basin, representing the middle reaches of the Heihe River basin. The method proposed is a combination of the daily SEBS results and data collected by meteorological stations. The result shows that the annual ET increased gradually during the period 1990-2004 and the main impact factor on the long-term increase of annual ET was the vegetation change. The accuracy of the ET result is validated using a water balance for the whole watershed and the validation reveals that the SEBS algorithm can be used to effectively estimate annual ET in the Zhangye basin. Chapter 4 establishes the quantitative relationship between the runoff of the Heihe River and the long-term vegetation change of the Ejina oasis, located in the lower reaches of the Heihe River. In this part, two time periods are distinguished corresponding to before and after the implementation of a new water allocation scheme in the Heihe River basin. The GIMMS NDVI and MODIS NDVI data sets are used to quantify the long-term change of the oasis vegetation in the first period 1989-2002 and the second period 2000-2006, respectively. The vegetation change shows a decreasing trend from 1989 to 2002 and an increasing trend between 2000 and 2006. Good relation between the runoff of the river and the vegetation growth are found at both stages and the time lag of the observed hysteresis effect of the runoff of the river on the oasis vegetation is one year. In addition, the yearly smallest water amount which sustains the demand of the eco-environment of the Ejina area is estimated to be 4×108 m3 based on MODIS images. Chapter 5 explores a method to quantify the effect of the groundwater depth on the vegetation growth in the year 2000 in the oasis area by combining MODIS NDVI with groundwater observation data. The result demonstrates that the groundwater depth suitable for vegetation growth in this region ranges from 2.8 to 5 m, depending on species composition. Hardly any vegetation growth occurs when the groundwater depth is below 5 m because the rooting depth of the occurring species is limited and cannot maintain adequate water supplies to their canopies when the water depth is below 5 m. The situation changes after implementation of the new water allocation scheme since 2000. The mean NDVI increased and the annual conversion of bare land into vegetated land is about 38 km2 per year during the period 2000 – 2008. It reflects a potential recovery of the eco-environment of the Ejina area. Chapter 6 comprises the main conclusions and the outlook for possible improvements in future research. The main contribution of this study is the successful integration of remote sensing with ecohydrology in quantifying the relationship between water resources and vegetation occurrence at large scale. It provides a methodology to evaluate the long-term vegetation change and the water resources impact using remote sensing data in water-limited areas. The approach of vegetation dynamics, runoff and groundwater impacts presented in this thesis serves as a sound foundation for predicting the effects of future environmental changes. <br/

Bird Species Diversity in Turkey and Remote Sensing Habitat Parameters

Thesis (M.Sc.) -- İstanbul Technical University, Eurasia Institute of Earth Sciences, Yüksek LisansTez (eng) -- İstanbul Teknik Üniversitesi, Avrasya Yer Bilimleri Enstitüsü, Yüksek LisansEcosystems are large and difficult to access. Therefore, it is difficult to measure the biodiversity. However, The development of various remote sensing technologies makes ecosystem research easier and more accurate than ever before. In this thesis, MODIS was used in the main study of Turkey as a whole, and LiDAR was used in further studies in some parts of the Black Sea. It is inevitable that biodiversity is decreasing worldwide. Various natural and physical influences are changing the living place. This study was geared towards birds living in Turkey. Bird populations and species are also decreasing in Turkey due to environmental and climate changes. (boyla et al, 2019). This study identified the relationship between bird species richness and vegetation, which is considered a major habitat for birds. Several studies have already shown that they are positively correlated.(Liang et al, 2018; Seto et al, 2004) There is a need to identify Turkey as a case. I wanted to see if the relationship could be confirmed with the vegetation index, a single parameter. Analysis of the relationship between all bird species and vegetation observed in Turkey, including species that do not have vegetation as their habitat. Remote sensing data was used to obtain vegetation information. The study used NDVI and EVI via MODIS Terra. First, I mapped three years of changes in NDVI and EVI from 2015 to 2017 throughout Turkey. All of them decreased every year. The trend were similar, but EVI was generally lower than NDVI, as usual. The map shows that the vegetation of the central inland regions of Turkey is further reduced. To check the relationship with the obtained vegetation index, bird species data was extracted from Turkish Breeding bird atlas data during the same 2015-2017 period was identified. Both NDVI and EVI showed a positive correlation with the bird species data. Especially, the maximum value of NDVI correlated strongly with Bir Species Richness. And, the mean values were most correlated in EVI. It is believed that EVI is sensitive to the terrain. (Matsushita et al, 2007) In addition, the correlation with 2017 was highist. Even 2015 EVI was analyzed to be independent of bird species richness. It was found that the Species richness at the same time has changed with the decrease of vegetation. The results of this study provide an overall review of the positive correlation between bird species richness and vegetation in Turkey. Furthermore, the usefulness of NDVI and EVI was confirmed again. After the main research as above, to understand the forest area in some areas a more detailed study was attempted. Further research on forest structure and bird diversity in local areas has been conducted. I used light detection and ranging (LiDAR) to collect more accurate high-resolution data for forest structure analysis. The two forests of each 0.4 km wide and 10 km long are selected from the forests with high bird species richness and relatively low bird species richness and their structural analysis using the LiDAR poind cloud data and the CHMs classification which one of forest metrics greatest influence on birds habitat. In addition, I used forest management plans data to analyze the differences in specific tree types and growth levels in each region. Under the assumption that species observed in the Atlas square (50km x 50km), can live in or stay in all the forests in that square. The results were that CHM was similar in overall trend, but the region with high species richness of bird had a higher proportion of '10 -20m ' than the low species richness region. Through the DEM, I could find many ridgelines, including steep slopes in the region with high specie richness. In addition, The region of high specie richness of bird had more varieties of trees than low specie richness region. DBH proportion was '8-19.9cm' of non-thick trees was high. At the top crown closure level, it was confirmed that both areas were dense forests with a high degree of closure. It results show the effectiveness of LiDAR in assessing forest health and productivity, and assessing habitat quality. Continued research into forests and habitats using various techniques such as LiDAR can lead to the creation of appropriate wildlife habitat models to build ecological forest management. Comprehensive correlation analyzes between habitat and other factors, climate change and forest structure etc, are required. Climate and physical changes at the time of the change in vegetation should also be identified. In order to maintain biodiversity, further research should be conducted to identify what changes are being made to the ecosystem and why these changes have occurred.Ekosistemleri geniş ve erişilmesi güçtür. Bu yüzden, biyoçeşitliliği ölçmek zordur. Ancak gelişen çeşitli uzaktan algılama sitemleri teknolojileri ile ekosistem araştırmaları hiç olmadığı kadar kolay ve doğru hale gelmiştir. Bu tezinin ana çalışmasında MODIS kullanılmıştır. Ek olarak Karadeniz'in bazı bölgelerinin detaylı bir çalışmasında LiDAR kullanılmıştır. Biyoçeşitlilğin dünya çapında azalması kaçınılmaz. Çeşitli doğal ve fiziksel etkiler yaşam alanlarını değiştirmekte. Bu çalışma Türkiye'de yaşayan kuşlara yöneliktir.Türkiye'de kuş nüfusu ve türleri de çevresel ve iklim değişikliklerinden dolayı azalmaktadır. (boyla et al, 2019). Bu çalışma kuş türleri için başlıca habitat olarak kabul edilen bitki örtüsü ve kuş türü zenginliği arasındaki ilişkiyi tanımlamıştır.Bir çok çalışma aralarındaki pozitif korelasyonu ortaya çıkarmıştır. .(Liang et al, 2018; Seto et al, 2004) Ancak Türkiye'ye ayrı bir tanımlama gerekmektedir. Habitatında bitki örtüsü olmayan kuşlar dahil olmak üzere Türkiye'deki tüm tür sayıları tek bir parametre olan bitki örtüsü indeksi ile ilişkilendirip ilişkilendirilemeyeceğini görmek istedim. Bitki örtüsü bilgisini elde etmek için uzaktan algılama verileri kullanılmıştır. Çalışmada MODIS Terra aracılığı ile NDVI ve EVI kullanılmıştır.Öncelikle 2015'ten 2017'ye Türkiye genelinde NDVI ve EVI deki değişiklikleri haritaladım. Hepsi her yıl düşüş gösterdi. Eğilim benzerdi ancak, EVI genellikle her zamanki gibi NDVI'dan düşüktü. Harita Türkiye'nin iç bölgelerinin bitki örtüsünün azaldığını göstermektedir. 2015-2017 yıllarında yapılan Türkiye Kuş yetiştirme atlas verilerinde kuş türleri arasındaki ilişki tespit edilmiştir. Hem NDVI hem de EVI kuş türleri verileri pozitif bir korelasyon göstermiştir.Özellikle NDVI'ın maksimum değeri kuş türü zenginliği ile büyük bir ilişki göstermiştir ve ortalama değerler en çok EVI ile ilişki göstermiştir. EVI'nin araziye duyarlı oluduğuna inanılır. (Matsushita et al, 2007) Ek olarak, 2017 ile en çok ilişki göstermektedir. 2015 EVI bile kuş türü zenginliğinden bağımsız olarak analiz edildi. Bu sayade, tür zenginliğinin bitki örtüsünün azamasıyla değiştiğini tespit ettik. Bu çalışmanın sonuçları Türkiye'deki kuş türü zenginliği ile bitki örtüsü arasındaki pozitif ilişkinin genel bir incelemesini sunmaktadır.Dahası, NDVI ve EVI'nin kullanılışlığı tekrar doğrulandı. Yukarıdaki ana araştırmadan sonra, bazı ormanlık alanları anlamak için daha ayrıntılı çalışmalar denendi. Karadeniz alanlarda orman yapısı ve kuş çeşitliliği hakkında daha fazla araştırma yapılmıştır. Buna örnek olarak orman yapısını doğru yüksek çözünürlüklü verilerle analiz etmek için "Light Detection and Ranging(LiDAR)" kullanıldı. Türkiye'de Üreyen Kuş Atlası kullanılarak kuşların bol olduğu ve nispeten düşük olduğu alanlar seçildi. 0.4 km ve 10 km uzunluğunda LiDAR nokta bulutu verilerini kullanılarak Vejetasyon Sınıflaması ve Yükseklik Modeli (DEM), Sayısal Yüzey Modeli (DSM) ve Canopy Yüksekliği Modeli (CHM) analiz edildi. Çalışma alanlarındaki ağaç türleri ve ağaç büyüme düzeyindeki farklılıkları kontrol etmek için amenajman planı ve meşcere haritası verileri kullanılmıştır. Sonuç olarak, genel CHMs eğilimleri benzer fakat tür habitatı zengin alanlar, düşük alanlardan '10 -20m' daha yüksekti. Ek olarak, DEM ile yapılan ölçümlerde kuş türü zengin alanda dik yamaçlar ve eğimler de bulunmaktaydı. Kuş türlerinin zengin olduğu alanda daha fazla ağaç türü vardı. Bu, orman türlerinin biyoçeşitliliği yüksek olduğunu göstermektedir. Gelişme çağları ise, kuş türlerinin zengin olduğu alanda çapları '8-19.9 cm' aralığında olan ağaçların oranı yüksekti. Tepe kapalılığı her iki alan da yüksek derecede tam kapalılığa sahip ormanlardı. Sonuçlarımız LiDAR'ın orman sağlığını, verimliliğini ve habitat kalitesini değerlendirme etkinliğini göstermektedir. LiDAR gibi çeşitli teknolojiler kullanılarak ormanlar ve habitatlar üzerine yapılan araştırmalar, uygun habitat modelleri oluşturularak ekolojik orman yönetimi oluşturulmasına yardımcı olacaktır. Habitat ve diğer föktörler, iklim değişikliği, ormanların yapısı vb. arasında kapsamlı ilişki analizleri gerekmektedir.Birki örtüsündeki değişim sırasındaki iklim ve fiziksel değişiklikler de tanımlanmalıdır.M.Sc.Yüksek Lisan

Earth Observations for Addressing Global Challenges

"Earth Observations for Addressing Global Challenges" presents the results of cutting-edge research related to innovative techniques and approaches based on satellite remote sensing data, the acquisition of earth observations, and their applications in the contemporary practice of sustainable development. Addressing the urgent tasks of adaptation to climate change is one of the biggest global challenges for humanity. As His Excellency António Guterres, Secretary-General of the United Nations, said, "Climate change is the defining issue of our time—and we are at a defining moment. We face a direct existential threat." For many years, scientists from around the world have been conducting research on earth observations collecting vital data about the state of the earth environment. Evidence of the rapidly changing climate is alarming: according to the World Meteorological Organization, the past two decades included 18 of the warmest years since 1850, when records began. Thus, Group on Earth Observations (GEO) has launched initiatives across multiple societal benefit areas (agriculture, biodiversity, climate, disasters, ecosystems, energy, health, water, and weather), such as the Global Forest Observations Initiative, the GEO Carbon and GHG Initiative, the GEO Biodiversity Observation Network, and the GEO Blue Planet, among others. The results of research that addressed strategic priorities of these important initiatives are presented in the monograph

Monitoring, Modelling and Management of Water Quality

Different types of pressures, such as nutrients, micropollutants, microbes, nanoparticles, microplastics, or antibiotic-resistant genes, endanger the quality of water bodies. Evidence-based pollution control needs to be built on the three basic elements of water governance: Monitoring, modeling, and management. Monitoring sets the empirical basis by providing space- and time-dependent information on substance concentrations and loads, as well as driving boundary conditions for assessing water quality trends, water quality statuses, and providing necessary information for the calibration and validation of models. Modeling needs proper system understanding and helps to derive information for times and locations where no monitoring is done or possible. Possible applications are risk assessments for exceedance of quality standards, assessment of regionalized relevance of sources and pathways of pollution, effectiveness of measures, bundles of measures or policies, and assessment of future developments as scenarios or forecasts. Management relies on this information and translates it in a socioeconomic context into specific plans for implementation. Evaluation of success of management plans again includes well-defined monitoring strategies. This book provides an important overview in this context

Balanço de energia com base no modelo S-SEBI sobre gramíneas em Barrax, Espanha e no bioma Pampa do sul do Brasil

No Brasil, existem seis biomas, sendo eles Amazônia, Mata Atlântica, Cerrado, Caatinga, Pantanal e Pampa. Cada bioma possui características únicas e importantes para a manutenção dos seus processos ecossistêmicos. Neste sentido, no bioma Pampa há uma dinâmica socioambiental que influencia a vegetação, o manejo agrícola e o modo de vida da população local. Este bioma é único no mundo porque traz na vegetação rasteira sua fonte de biomassa e energia como em nenhum outro ecossistema, seus campos nativos são os responsáveis pela conservação e preservação dos recursos hídricos, da fauna silvestre e da biodiversidade. A supressão da vegetação nativa deste bioma para a monocultura de grãos compromete a manutenção da biodiversidade e gera impactos nos recursos naturais, alterando as suas condições ambientais, a disponibilidade de água e a temperatura de superfície. Além disso, as mudanças climáticas têm modificado os componentes do Balanço de Energia (BE). Em relação ao balanço energético este bioma tem, no estado do Rio Grande do Sul, a mesma importância climática que as florestas em regiões tropicais, já que cobre 63% do Estado e possui influência nas dinâmicas atmosféricas. Sendo assim, o objetivo deste trabalho é avaliar as particularidades ambientais do BE e do cálculo de evapotranspiração (ET) no bioma Pampa. A ET é a responsável pelas interações da biosfera- atmosfera-hidrosfera. Estas interações se dão por utilizar energia eletromagnética para a formação de vapor d’água a partir da transpiração vegetal e da evaporação da água. O uso do Sensoriamento Remoto tem sido eficaz nas estimativas de fluxo de calor sensível e fluxo de calor latente por diferentes métodos, porém a aplicação de forma operacional, a heterogeneidade da superfície e a influência da temperatura de superfície (Ts) são desafios deste trabalho. O modelo S-SEBI para recuperação de dados de ET foi avaliado no bioma Pampa e em Barrax, um sítio de validação localizado no mediterrâneo espanhol. O modelo demonstrou ser eficaz em vegetação campestre, além de ser menos dependente da Ts em relação a outros modelos reportados na literatura. Os resultados deste trabalho visam contribuir para a geração de melhor qualidade de dados de ET em futuras análises de mudanças de uso do solo, mudanças climáticas e gestão dos recursos hídricos para todo o bioma Pampa.In Brazil, there are six biomes, namely the Amazon, Atlantic Forest, Cerrado, Caatinga, Pantanal, and Pampa. Each biome has unique and important characteristics for the maintenance of the ecosystemic processes of each environment. In this sense, in the Pampa biome there is a socio-environmental dynamic that influences the vegetation, agricultural management, and the way of life of the local population. This biome is unique in the world because it brings in its undergrowth vegetation its source of biomass and energy like no other ecosystem; its native grasslands are responsible for the conservation and preservation of water resources, wildlife, and biodiversity. The suppression of the native vegetation of this biome for the monoculture of grains compromises the maintenance of biodiversity and generates impacts on natural resources, altering the environmental conditions of the ecosystem, water availability, and surface temperature. In addition, climate change has modified the components of the Energy Balance (EB). In relation to the energy balance, in the state of Rio Grande do Sul, this biome has the same climatic importance as the forests in tropical regions, since it covers 63% of the state and influences the atmospheric dynamics. Therefore, the objective of this work is to evaluate the environmental particularities of BE and the calculation of evapotranspiration (ET) in the Pampa biome. ET is responsible for biosphere-atmosphere-hydrosphere interactions. These interactions occur by using electromagnetic energy for the formation of water vapor from plant transpiration and water evaporation. The use of Remote Sensing has been effective in estimating sensible heat flux and latent heat flux by different methods, but the application in an operational way, the heterogeneity of the surface and the influence of the surface temperature (Ts) are challenges of this work. The S-SEBI model for ET data retrieval was evaluated in the Pampa biome and in Barrax, a validation site located in the Spanish Mediterranean. The model proved to be effective in grassland vegetation, and is less dependent on Ts compared to other models reported in the literature. The results of this work aim to contribute to the generation of better quality ET data in future analyses of land use change, climate change, and water resource management for the entire Pampa biome

Advances in Hydraulics and Hydroinformatics Volume 2

This Special Issue reports on recent research trends in hydraulics, hydrodynamics, and hydroinformatics, and their novel applications in practical engineering. The Issue covers a wide range of topics, including open channel flows, sediment transport dynamics, two-phase flows, flow-induced vibration and water quality. The collected papers provide insight into new developments in physical, mathematical, and numerical modelling of important problems in hydraulics and hydroinformatics, and include demonstrations of the application of such models in water resources engineering

Fruit Tree Responses to Water Stress: Automated Physiological Measurements and Rootstock Responses

New orchard plantings utilize trees grafted to dwarfing rootstocks planted close together to facilitate larger harvests. These dwarfing rootstocks have not been comprehensively studied for their ability to withstand drought. This is of special importance in the Intermountain West which has limited rainfall. Additionally, orchard growers face competition for water from a growing population and increased uncertainty in rainfall from climate change. My research examined the use of dendrometers, which measure changes in trunk diameter, and sap flow sensors, which measure how quickly sap moves, as methods to inform growers about tree water status. I also used a weighing lysimeter system to measure tree water use in four different rootstocks as they were subjected to drought. In a field study, I placed dendrometers and sap flow sensors in a high-density apple orchard. As the trees progressed through the season and put on fruit the responses from the sensors changed. By separating data from the sap flow sensors and dendrometers into seasons, their ability to predict tree water status improved. I found that overall dendrometers would be the best way to automate measurements of tree water status. In my first rootstock trial I examined responses of peach trees grown from seeds from an orchard maintained by Navajo farmers in South Western Utah, and a commercially available rootstock. I found that the Navajo peach trees put on more growth than the commercial trees despite drought, which suggests that they may be useful for rootstock development. In my second rootstock trial I examine the commercially available Krymsk® 5 and 6 series dwarfing cherry rootstocks for responses to drought. I found that the Krymsk® 6 rootstocks had higher rates of transpiration and used water faster than the Krymsk® 5 allowing them to put on growth quickly even during drought. Krymsk® 5 rootstocks have a lower percentage of their biomass in their roots which may have helped to conserve water