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PyLUR:Efficient software for land use regression modeling the spatial distribution of air pollutants using GDAL/OGR library in Python

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Frontiers of Environmental Science & Engineering 2020年第3期14卷 89-102页

作者： Xuying Ma Ian Longley Jennifer Salmond jay gao School of Environment Faculty of ScienceUniversity of AucklandAuckland 1010New Zealand National Institute of Water and Atmospheric Research Auckland 1010New Zealand

Land use regression(LUR)models have been widely used in air pollution *** regressionbased approach estimates the ambient pollutant concentrations at un-sampled points of interest by considering the relationship between ambient concentrations and several predictor variables selected from the surrounding *** conceptually quite simple,its successful implementation requires detailed knowledge of the area,expertise in GIS,statistics,and programming skills,which makes this modeling approach relatively inaccessible to novice *** this contribution,we present a LUR modeling and pollution-mapping software named *** uses GDAL/OGR libraries based on the Python platform and can build a LUR model and generate pollutant concentration maps *** self-developed software comprises four modules:a potential predictor variable generation module,a regression modeling module,a model validation module,and a prediction and mapping *** performance of the newly developed PyLUR is compared to an existing LUR modeling software called RLUR(with similar functions implemented on R language platform)in terms of model accuracy,processing efficiency and software *** results show that PyLUR out-performs RLUR for modeling in the Bradford and Auckland case studies ***,PyLUR is much more efficient in data processing and it has a capability to handle detailed GIS input data.

关键词： LUR Air pollution modelling GIS spatial analysis GDAL/OGR Python Pollutant concentration mapping

Topographic Influence on Wetland Distribution and Change in Maduo County, Qinghai-Tibet Plateau, China

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Journal of Mountain Science 2012年第3期9卷 362-371页

作者： jay gao LI Xilai Gary BRIERLEY School of Environment University of Auckland lo Symonds Street Auckland New Zealand College of Agriculture andAnimal Husbandry Qinghai University Xining 810016 China

Accurate information on the spatial distribution and temporal change of wetlands is vital to devise effective measures for their protection. This study uses satellite images in 1994 and 2001 to assess the effects of topography and proximity to channels on wetland change in Maduo County on the Qinghai-Tibet Plateau, western China. In 1994 wetlands in the study area extended over 6,780.0 km2. They were distributed widely throughout the county, with a higher concentration in the south, and were especially prominent close to streams. The pattern of wetlands demonstrated a bell-shaped distribution curve with elevation, ranging over hill slopes with gradients from 0-19°, the commonest gradient being around 3°. Although the aspects of these hill slopes range over all directions, there is a lower concentration of wetlands facing east and southeast. The extent of wetlands in 2001 decreased to 6,181.1 km2. Marked spatial differentiation in the pattern of wetlands is evident, as their area increased by 1,193.3 km2 at lower elevations but decreased by 1,792.2 km2 at higher ground, resulting in a net decrease of 598.8 km2. In areas with a gradient 9° the area of wetlands remained approximately consistent from 1994-2001. Newly retained wetlands are situated in relatively flat lowland areas, with no evident preference in terms of aspect. Wetlands on north-, east- and northeast-facing hillslopes with a bearing of 1-86° were more prone to loss of area than other orientations. The altered pattern of wetland distribution from higher to lower elevation on north-facing slopes coincided with the doubling of annual temperature during the same period, suggesting that climate warming could be an important cause.

关键词： Wetland change detection Topographicinfluence Remote Sensing GIS Qinghai-TibetPlateau

Remote sensing-based estimation of rice yields using various models:A critical review

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Geo-Spatial Information Science 2021年第4期24卷 580-603页

作者： Daniel Marc G dela Torre jay gao Cate Macinnis-Ng School of Environment University of AucklandAucklandNew Zealand School of Biological Sciences University of AucklandAucklandNew Zealand

Reliable estimation of region-wide rice yield is vital for food security and agricultural ***-scale models have increased our understanding of rice yield and its estimation under theoretical environmental ***,they offer little infor-mation on spatial variability effects on farm-scale *** Sensing(RS)is a useful tool to upscale yield estimates from farm scales to regional *** research used RS with rice models for reliable yield *** several countries start to operatio-nalize rice monitoring systems,it is needed to synthesize current literature to identify knowledge gaps,to improve estimation accuracies,and to optimize *** paper critically reviewed significant developments in using geospatial methods,imagery,and quantitative models to estimate rice ***,essential characteristics of rice were discussed as detected by optical and radar sensors,band selection,sensor configuration,spatial resolution,mapping methods,and biophysical variables of rice derivable from RS ***,various empirical,process-based,and semi-empirical models that used RS data for spatial estimation of yield were critically assessed-discussing how major types of models,RS platforms,data assimilation algorithms,canopy state variables,and RS variables can be integrated for yield ***,to overcome current constraints and to improve accuracies,several possibilities were suggested-adding new modeling modules,using alternative canopy variables,and adopting novel modeling *** rice yields are expected to decrease due to global warming,geospatial rice yield estimation techniques are indispensable tools for climate change *** studies should focus on resolving the current limitations of estimation by precise delineation of rice cultivars,by incorporating dynamic harvesting indices based on climatic drivers,using innovative modeling approaches with machine learning.

关键词： Process-based crop model data assimilation empirical model geospatial applications remote sensing rice yield mapping yield estimation

Degradation of Wetlands on the Qinghai-Tibet Plateau:A Comparison of the Effectiveness of Three Indicators

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Journal of Mountain Science 2013年第4期10卷 658-667页

作者： gao jay LI Xi-lai CHEUNG Alan YANG Yuan-wu School of Environment University of Auckland Private Bag 92019Auckland New Zealand College of Agriculture and Animal Husbandry Qinghai University College of Agriculture and Animal Husbandry Qinghai UniversityXining 810016 China

The Qinghai-Tibet Plateau encompasses a large quantity of wetlands, some of which have been degraded to varying severity levels. In the literature, a number of degradation indicators have been proposed to evaluate ecological health of wetlands, but their effectiveness in the plateau environment remains unknown. In this study, we assessed the effectiveness of three degradation indicators, soil moisture content at lo em deep, vegetative cover, and density of pika burrows. The degradation severity of wetlands in Maduo County on the Qinghai-Tibet Plateau is enumerated at four levels, intact, slight, moderate and severe. Analysis of xo6 samples collected in the field demonstrates that the density of pika burrows is the least reliable indicator. By comparison, vegetative cover and underlying soil moisture content are more reliable, even though neither is a perfect indicator as the difference among adjacent levels of severity as revealed by t-test is not always statistically significant. The imperfection of vegetative cover as an indicator is due to its variation among different types of wetlands. The limitation of moisture content is attributed to its non-linear relationship with wetland degradation. Above the threshold of about 50% in moisture content wetlands are unlikely to be degraded. It is recommended that moisture be measured at the point near the surface and vegetative cover be further differentiated by species in order to improve their effectiveness.

关键词： Wetland degradation Grass cover Soilmoisture Pika damage Qinghai-Tibet Plateau

Phenology-based delineation of irrigated and rain-fed paddy fields with Sentinel-2 imagery in Google Earth Engine

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Geo-Spatial Information Science 2021年第4期24卷 695-710页

作者： Daniel Marc G.dela Torre jay gao Cate Macinnis-Ng Yan Shi School of Environment University of AucklandAucklandNew Zealand School of Biological Sciences University of AucklandAucklandNew Zealand

Paddy rice agriculture is practiced in both rain-fed and irrigated ecosystems in the ***,small farms are prevalent in the region,and current satellite-based mapping techniques do not distinguish between the two ecosystems at farm *** study developed an approach to rapidly map irrigated and rain-fed paddy rice in Iloilo,Philippines at 10 m resolutions using Google Earth *** approach used an ensemble of classifiers based on time-series vegetation indices to produce dry and wet seasonal maps for the entire *** showed a predominance of rain-fed rice areas in both seasons,with irrigated rice making up only onefourth of the total rice *** overall accuracy was achieved at 68%for the dry season and 75%for the wet season based on ground-acquired points and very high-resolution *** two types of paddies were classified at accuracies up to 87%.Furthermore,the land cover maps showed a strong agreement with the municipal *** resultant maps complement current official statistics and demonstrate the prowess of phenology-based mapping to create paddy inventories in a timely manner to inform food security and agricultural policies.

关键词： Phenology-based mapping paddy type Google Earth Engine Sentinel-2 rice mapping

Geomorphic-centered Classification of Wetlands on the Qinghai-Tibet Plateau, Western China

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Journal of Mountain Science 2013年第4期10卷 632-642页

作者： gao jay LI Xi-lai Gary BRIERLEY Alan CHEUNG YANG Yuan-wu School of Environment University of Auckland Private Bag 92019Auckland New Zealand College of Agriculture and Animal Husbandry Qinghai University

In this paper a geomorphic-centered system was proposed for classifying the wetlands on the Qinghai-Tibet Plateau in western China, where the flora comprises primarily grasses. Although the geomorphic properties (e.g., elevation and morphology) of wetlands form the primary criteria of classification, this system also takes hydrological processes into implicit consideration. It represents an improvement over the hydrogeomorphic perspective as the relative importance of the two components (wetness and landform) of wetlands is clearly differentiated. This geomorphic-centered perspective yields insights into the hydrogeomorphic dynamics of plateau wetlands while indicates their vulnerability to change and degradation indirectly. According to this geomorphic-centered perspective, all plateau wetlands fall into one of the seven types of alpine, piedmont, valley, terrace, floodplain, lacustrine, and riverine in three elevational categories of upland, midland, and lowland. Upland (alpine and piedmont) wetlands with the steepest topography are the most sensitive to change whereas midland (floodplain, terrace and valley) wetlands are less vulnerable to degradation owing to a high water reserve except terrace wetlands. They have a dry surface caused by infrequent hydrological replenishment owing to their higher elevation than the channel. Low lying (lacustrine and riverine) wetlands are the most resilient. The geomorphic-centered perspective developed in this paper provides a framework for improving recognition and management of wetlands on the Plateau. Resilient wetlands can be grazed more intensively without the risk of degradation. Fragile and vulnerable wetlands require careful managementto avoid degradation.

关键词： Plateau wetlands Geomorphieclassification Wetland vulnerability Qinghai-TibetPlateau

Restoration Prospects for Heitutan Degraded Grassland in the Sanjiangyuan

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Journal of Mountain Science 2013年第4期10卷 687-698页

作者： LI Xi-lai PERRY LW George BRIERLEY Gary gao jay ZHANG Jing YANG Yuan-wu College of Agriculture and Animal Husbandry Qinghai University School of Environment University of Auckland New Zealand Private Bag 92019Auckland New Zealand School of Biological Sciences University of Auckland New Zealand Private Bag 92019Auckland New Zealand

In many ecosystems ungulates have coexisted with grasslands over long periods of time. However, high densities of grazing animals may change the floristic and structural characteristics of vegetation, reduce biodiversity, and increase soil erosion, potentially triggering abrupt and rapid changes in ecosystem condition. Alternate stable state theory provides a framework for understanding this type of dynamic. In the Sanjiangyuan atop the Qinghai-Tibetan plateau (QTP), grassland degradation has been accompanied by irruptions of native burrowing animals, which has accentuated the loss of ground cover. Severely degraded areas of alpine meadows are referred to as 'Heitutan'. Here, using the framework of alternate stable state theory, we describe the proximate and ultimate drivers of the formation of Heitutan on the QTP, and we assess prospects for recovery, in relation to the degree of biophysical alteration, of these alpine meadows. Effective rehabilitation measures must address the underlying causes of degradation rather than their symptoms. Heitutan degradation is not uni-causal. Rather it reflects different mechanisms operating at different spatio-temporal scales across this vast region. Underlying causes include overly aggressive exploitation of the grasslands (e.g. overgrazing), amplification of grazing and erosion damage by small mammals when outbreaks occur, and/or climate change. Given marked variability in environmental conditions and stressors, restorative efforts must vary across the region. Restoration efforts are likely toyield greatest success if moderately and severely degraded areas are targeted as the first priority in management programmes, before these areas are transformed into extreme Heitutan.

关键词： Heitutan degraded grassland Alpinemeadow Restoration/rehabilitation Sanjiangyuan Qinghai-Tibet Plateau (QTP)

Health assessment of plantations based on LiDAR canopy spatial structure parameters

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International Journal of Digital Earth 2022年第1期15卷 712-729页

作者： Pengyu Meng Hong Wang Shuhong Qin Xiuneng Li Zhenglin Song Yicong Wang Yi Yang jay gao School of Hydrology and Water resources Hohai UniversityNanjingPeople’s Republic of China School of Earth Science and Engineering Hohai UniversityNanjingPeople’s Republic of China School of Environment Faculty of ScienceUniversity of AucklandAucklandNew Zealand

The Yellow River Delta(YRD)has China's largest artificial Robinia pseudoacacia forest,which was planted in the late 1970s and suffered extensive dieback in the *** health grade of the *** forest(named canopy vigor grade,CVG)could be achieved by using high-resolution images and canopy vigor indicators(CVIs).However,a previous study showed that there was no significant correlation between CVG and the field-estimated aboveground biomass(AGB)of *** ***,this study aims to construct forest health indicators(FHIs)based on canopy spatial structure parameters extracted from *** FHIs included Weibull_α(the scale parameter of the Weibull density function that reflects the shape of the tree canopy),VCI(vertical complexity index),sdCC(the standard deviation of canopy cover),H99(the 99th percentile height)and cvLAD(the coefficient of variation of leaf area density),and could significantly distinguish three forest health grades(FHG)(p<0.05).The FHG was positively correlated with forest AGB(rs=0.51,p=0.004),and the similarity value with CVG was 63.33%.The results of this study confirmed that the FHIs can reflect both canopy vigor and tree productivity,and distinguish forest health status without prior classification information.

关键词： Forest health indicators LiDAR structural parameter Robinia pseudoacacia forest the Yellow River Delta

Sustainable Exploitation of Land Resources:How can it benefit from modern geoinformatic technologies?

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Sustainable Exploitation of Land Resources:How can it benefi...