Active‐Passive Surface Water Classification: A New Method for High‐Resolution Monitoring of Surface Water Dynamics

The airborne AirSWOT instrument suite, consisting of an interferometric Ka-band synthetic aperture radar and color-infrared (CIR) camera, was deployed to northern North America in July and August 2017 as part of the NASA Arctic-Boreal Vulnerability Experiment (ABoVE). We present validated, open (i.e., vegetation-free) surface water masks produced from high-resolution (1 m), co-registered AirSWOT CIR imagery using a semi-automated, object-based water classification. The imagery and resulting high-resolution water masks are available as open-access datasets and support interpretation of AirSWOT radar and other coincident ABoVE image products, including LVIS, UAVSAR, AIRMOSS, AVIRIS-NG, and CFIS. These synergies offer promising potential for multi-sensor analysis of Arctic-Boreal surface water bodies. In total, 3167 km2 of open surface water were mapped from 23,380 km2 of flight lines spanning 23 degrees of latitude and broad environmental gradients. Detected water body sizes range from 0.00004 km2 (40 m2) to 15 km2. Power-law extrapolations are commonly used to estimate the abundance of small lakes from coarser resolution imagery, and our mapped water bodies followed power-law distributions, but only for water bodies greater than 0.34 (±0.13) km2 in area. For water bodies exceeding this size threshold, the coefficients of power-law fits vary for different Arctic-Boreal physiographic terrains (wetland, prairie pothole, lowland river valley, thermokarst, and Canadian Shield). Thus, direct mapping using high-resolution imagery remains the most accurate way to estimate the abundance of small surface water bodies. We conclude that empirical scaling relationships, useful for estimating total trace gas exchange and aquatic habitats on Arctic-Boreal landscapes, are uniquely enabled by high-resolution AirSWOT-like mappings and automated detection methods such as those developed here.

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Monitoring Surface Water Dynamics in the Prairie Pothole Region Using Dual-Polarised Sentinel-1 SAR Time Series

10.5194/hess-2021-330 ◽

2021 ◽

Author(s):

Stefan Schlaffer ◽

Marco Chini ◽

Wouter Dorigo ◽

Simon Plank

Keyword(s):

Surface Water ◽

High Resolution ◽

Prairie Pothole Region ◽

Open Water ◽

Water Area ◽

Water Bodies ◽

Water Dynamics ◽

Prairie Pothole ◽

Small Water ◽

Small Water Bodies

Abstract. The North American Prairie Pothole Region (PPR) represents a large system of wetlands with great importance for biodiversity, water storage and flood management. Knowledge of seasonal and inter-annual surface water dynamics in the PPR is important for understanding the functionality of these wetland ecosystems and the changing degree of hydrologic connectivity between them. Optical sensors have been widely used to calibrate and validate hydrological models of wetland dynamics. Yet, they are often limited by their temporal resolution and cloud cover, especially in the case of flood events. Synthetic aperture radar (SAR) sensors, such as the ones on board the Copernicus Sentinel-1 mission, can potentially overcome such limitations. However, water extent retrieval from SAR data is often affected by environmental factors, such as wind on water surfaces. Hence, for reliably monitoring water extent over longer time periods robust retrieval methods are required. The aim of this study was to develop a robust approach for classifying open water extent dynamics in the PPR and to analyse the obtained time series covering the entire available Sentinel-1 observation period from 2015 to 2020 in the light of ancillary data. Open water in prairie potholes was classified by fusing dual-polarised Sentinel-1 data and high-resolution topographical information using a Bayesian framework. The approach was tested for a study area in North Dakota. The resulting surface water maps were validated using high-resolution airborne optical imagery. For the observation period, the total water area, the number of water bodies and the median area per water body were computed. The validation of the retrieved water maps yielded producer’s accuracies between 84 % and 95 % for calm days and between 74 % and 88 % on windy days. User’s accuracies were above 98 % in all cases, indicating a very low occurrence of false positives due to the constraints introduced by topographical information. Surface water dynamics showed strong intra-annual dynamics especially in the case of small water bodies (< 1 ha). Water area and number of small water bodies decreased from spring throughout summer when evaporation rates in the PPR are typically high. Larger water bodies showed a more stable behaviour during most years. During the extremely wet period between the autumn of 2019 and mid-2020, however, the dynamics of both small and large water bodies changed markedly. While a larger number of small water bodies was encountered, which remained stable throughout the wet period, also the area of larger water bodies increased, partly due to merging of smaller adjacent water bodies. However, the area covered by small water bodies was more stable than the area covered by large water bodies. This suggests that large potholes released water faster via the drainage network, while small potholes released water mainly to the atmosphere via evaporation. The results demonstrate the potential of Sentinel-1 data for high-resolution monitoring of prairie wetlands. Limitations exist related to wind inhibiting correct water extent retrieval and due to the rather low temporal resolution of 12 days over the PPR.

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New method for tree stands parameters determination using high resolution images done by unmanned aerial vehicle

Известия СПбЛТА ◽

10.21266/2079-4304.2016.215.6-18 ◽

2016 ◽

Author(s):

А.С. Алексеев ◽

А.А. Никифоров ◽

А.А. Михайлова ◽

М.Р. Вагизов

Keyword(s):

High Resolution ◽

Unmanned Aerial Vehicle ◽

New Method ◽

Growth And Yield ◽

Special Treatment ◽

Resolution Image ◽

Growing Stock ◽

High Resolution Image ◽

Aerial Vehicle ◽

Area Unit

В связи со старением информационных материалов о состоянии лесов существует потребность в разработке новых методов таксации древостоев, основанных на применении последних научно-технических достижений в области теории структуры и продуктивности древостоев, дистанционных методов изучения лесов, информационных и ГИС технологий. В статье приведены результаты разработки и проверки нового метода определения таксационных характеристик сомкнутых насаждений на основе правила 3/2 и подобных ему правил Хильми и Рейнеке, с одной стороны, и определения числа деревьев на единице площади по снимку сверх высокого разрешения, полученного с помощью БПЛА, с другой. С теоретической точки зрения эта зависимости величин запаса, средней высоты и среднего диаметра от числа стволов на единице площади относятся к классу аллометрических связей, очень часто встречающихся при количественном описании соотношений частей биологических систем разных уровней иерархии, от организмов до экосистем. Параметры аллометрических зависимостей запаса, средних высоты и диаметра от числа стволов на единице площади были определены для основных лесообразующих пород по данным таблиц хода роста нормальных (полных) древостоев с теоретическим показателем степени и затем использованы для расчетов. Число деревьев на единице площади определялось по снимку с разрешением 7,13 см/пиксель, полученному с помощью 4-роторной платформы. Обработка материалов аэрофотосъемки была выполнена в специализированной фотограмметрической системе Agisoft Photoscan. В результате были получены ортофотоплан и цифровая модель поверхности крон деревьев на изучаемую территорию с определением их высот. Для автоматизированной обработки полученных изображений с целью получения значений числа деревьев на единицу площади был создан специализированный скрипт на языке Java. Погрешности определения таксационных характеристик древостоев предлагаемым методом не выше установленных действующими нормативными материалами. Every time there is a demand for new innovative methods of forest resources estimation based on last achievements in theoretical science, remote sensing methods, information and GIS-technologies. In the paper are presented a new method and the results of its application to forest stands growing stock, mean height and diameter determination. The method is based on rule 3/2 and similar Reineke and Hilmy rules, on one hand and high resolution image made by unmanned aerial vehicle, which used for determination of number of trees per area unit, on other. The above rules are well known in quantitative biology as an allometric and widely used for description of different kind of relations in biological systems of various scale: from organisms to ecosystems. Parameters of above allometric relationships between growing stock, mean height and diameter and stems density per area unit was determine on the base of full stock growth and yield tables for main tree species and after used for experimental calculations. The number of trees per area unit was determined after special treatment of high resolution image made by unmanned flying machine. The growing stock, mean height and diameter determined by suggested method was compared with the data of regular forest inventory. Comparison gives positive result and method may be recommended for further development.

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Spectroscopic characterization of a thermodynamically stable doubly charged diatomic molecule: MgAr2+

Physical Chemistry Chemical Physics ◽

10.1039/d1cp00730k ◽

2021 ◽

Author(s):

Dominik Wehrli ◽

Matthieu Génévriez ◽

Frédéric Merkt

Keyword(s):

High Resolution ◽

Diatomic Molecule ◽

Spectroscopic Characterization ◽

New Method ◽

High Resolution Spectroscopy ◽

Singly Charged ◽

Doubly Charged

We present a new method to study doubly charged molecules relying on high-resolution spectroscopy of the singly charged parent cation, and report on the first spectroscopic characterization of a thermodynamically stable diatomic dication, MgAr2+.

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High-resolution modeling of LIDAR data Mechanisms governing surface water vapor variability during SALSA

Agricultural and Forest Meteorology ◽

10.1016/s0168-1923(00)00182-9 ◽

2000 ◽

Vol 105 (1-3) ◽

pp. 185-194 ◽

Cited By ~ 3

Author(s):

C Kao

Keyword(s):

Water Vapor ◽

Surface Water ◽

High Resolution ◽

Lidar Data

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Two-Step Urban Water Index (TSUWI): A New Technique for High-Resolution Mapping of Urban Surface Water

Remote Sensing ◽

10.3390/rs10111704 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1704 ◽

Cited By ~ 2

Author(s):

Wei Wu ◽

Qiangzi Li ◽

Yuan Zhang ◽

Xin Du ◽

Hongyan Wang

Keyword(s):

Surface Water ◽

High Resolution ◽

Urban Surface ◽

Mapping Technique ◽

Support Vector ◽

Svm Classifier ◽

P Value ◽

Urban Water ◽

Water Index ◽

Water Mapping

Urban surface water mapping is essential for studying its role in urban ecosystems and local microclimates. However, fast and accurate extraction of urban water remains a great challenge due to the limitations of conventional water indexes and the presence of shadows. Therefore, we proposed a new urban water mapping technique named the Two-Step Urban Water Index (TSUWI), which combines an Urban Water Index (UWI) and an Urban Shadow Index (USI). These two subindexes were established based on spectral analysis and linear Support Vector Machine (SVM) training of pure pixels from eight training sites across China. The performance of the TSUWI was compared with that of the Normalized Difference Water Index (NDWI), High Resolution Water Index (HRWI) and SVM classifier at twelve test sites. The results showed that this method consistently achieved good performance with a mean Kappa Coefficient (KC) of 0.97 and a mean total error (TE) of 2.28%. Overall, classification accuracy of TSUWI was significantly higher than that of the NDWI, HRWI, and SVM (p-value < 0.01). At most test sites, TSUWI improved accuracy by decreasing the TEs by more than 45% compared to NDWI and HRWI, and by more than 15% compared to SVM. In addition, both UWI and USI were shown to have more stable optimal thresholds that are close to 0 and maintain better performance near their optimum thresholds. Therefore, TSUWI can be used as a simple yet robust method for urban water mapping with high accuracy.

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A new method for TIMS high precision analysis of Ba and Sr isotopes for cosmochemical studies

Journal of Analytical Atomic Spectrometry ◽

10.1039/c7ja00012j ◽

2017 ◽

Vol 32 (7) ◽

pp. 1388-1399 ◽

Cited By ~ 9

Author(s):

Elsa Yobregat ◽

Caroline Fitoussi ◽

Bernard Bourdon

Keyword(s):

Mass Spectrometry ◽

High Resolution ◽

High Precision ◽

Thermal Ionization Mass Spectrometry ◽

New Method ◽

Ionization Mass ◽

Sr Isotopes ◽

Sr Resin ◽

Thermal Ionization Mass ◽

Isotope Measurements

A new protocol using Eichron™ Sr-resin for high-resolution Sr and Ba isotope measurements using thermal ionization mass spectrometry for cosmochemical samples.

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A new method for high-resolution bivalve growth rate studies in hydrothermal environments

Marine Biology ◽

10.1007/s00227-013-2195-7 ◽

2013 ◽

Vol 160 (6) ◽

pp. 1427-1439 ◽

Cited By ~ 18

Author(s):

K. Nedoncelle ◽

F. Lartaud ◽

M. de Rafelis ◽

S. Boulila ◽

N. Le Bris

Keyword(s):

Growth Rate ◽

High Resolution ◽

New Method ◽

Hydrothermal Environments

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Application of High-Resolution 3D Scanning in Medical Volumetry

International Journal of Electronics and Telecommunications ◽

10.1515/eletel-2016-0003 ◽

2016 ◽

Vol 62 (1) ◽

pp. 23-31 ◽

Cited By ~ 13

Author(s):

Adam Chromy

Keyword(s):

High Resolution ◽

Recovery Process ◽

3D Scanning ◽

Volumetric Method ◽

New Method ◽

Medical Applications ◽

Practical Application ◽

3D Scanner ◽

Standard Methods ◽

3D Scanners

Abstract This paper deals with application of 3D scanning technology in medicine. Important properties of 3D scanners are discussed with emphasize on medical applications. Construction of medical 3D scanner according to these specifications is described and practical application of its use in medical volumetry is presented. Besides volumetry, such 3D scanner is usable for many other purposes, like monitoring of recovery process, ergonomic splint manufacturing or inflammation detection. 3D scanning introduces novel volumetric method, which is compared with standard methods. The new method is more accurate compared to present ones. Principles of this method are discussed in paper and its accuracy is evaluated and experimentally verified.

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