sensitivity evaluation of spectral vegetation indices using sensitivity functions for stand volume estimation

نویسندگان
چکیده

identification of the best vegetation indices (vis) for use in quantitative analyzes of vegetation is one of the important issues for ecologists. the objective of this study was sensitivity evaluation of vegetation indices to a stand volume for identification of the best vegetation index (vi) in stand volume estimation using a statistical sensitivity method. also, another objective of this study was to compare results of stand volume estimation using sensitivity function and the best subset regression. we also evaluated sensitivity of vi relative to another vi using relative sensitivity function. in this study, 99 plots 60m×60m each were used with systematic cluster sampling method. in each plot, data on tree species, diameter at breast height, stand height and geographic coordinates of each plot center were recorded. the vegetation indices were created using landsat etm+ data. in order to analyze the relationship between stand volume and vegetation indices, average digital number of pixels within 2×2 pixels window were extracted from vegetation indices. the result of the sensitivity function showed that ndwi and greenness had high sensitivity compared to dvi, rai and gemi in stand volume estimation, respectively. therefore, ndwi and greenness were selected for estimating stand volume using satellite data. also, the result of the best subset regression analyses showed that dvi and ndwi were best for estimation of the stand volume. the regression model with ndwi and greenness could better predict stand volume (adjusted r2=55.4%) compared to dvi and ndwi (adjusted r2=43.5%). this is a 12% increase in adjusted r2. the results showed that relative sensitivity of ndwi to gemi and greenness is high. generally, the sensitivity function expresses the change in sensitivity of a vi through the range of allometric characteristics, it is irrelevant of the unit or magnitude of vegetation indices and it tests the significance of the sensitivity with t-or-z statistic is useful for evaluation of sensitivity analysis of vegetation indices and identifying the best vegetation indices in quantitative and qualitative assessment of forested area.

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Certified Metamodels for Sensitivity Indices Estimation

Global sensitivity analysis of a numerical code, more specifically estimation of Sobol indices associated with input variables, generally requires a large number of model runs. When those demand too much computation time, it is necessary to use a reduced model (metamodel) to perform sensitivity analysis, whose outputs are numerically close to the ones of the original model, while being much fas...

متن کامل

Viewing Geometry Sensitivity of Commonly Used Vegetation Indices towards the Estimation of Biophysical Variables in Orchards

Stress-related biophysical variables of capital intensive orchard crops can be estimated with proxies via spectral vegetation indices from off-nadir viewing satellite imagery. However, variable viewing compositions affect the relationship between spectral vegetation indices and stress-related variables (i.e., chlorophyll content, water content and Leaf Area Index (LAI)) and could obstruct chang...

متن کامل

Green Leaf Area Index Estimation in Maize and Soybean: Combining Vegetation Indices to Achieve Maximal Sensitivity

Published in Agron. J. 104:1336–1347 (2012) Posted online 29 June 2012 doi:10.2134/agronj2012.0065 Copyright © 2012 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and ret...

متن کامل

Estimation of global sensitivity indices for models with dependent variables

A novel approach for estimation variance based sensitivity indices for models with dependent variables is presented. Both the first order and total sensitivity indices are derived as generalizations of Sobol’ sensitivity indices. Formulas and Monte Carlo numerical estimates similar to Sobol’ formulas are derived. A copula based approach is proposed for sampling from arbitrary multivariate proba...

متن کامل

Rank-based camera spectral sensitivity estimation.

In order to accurately predict a digital camera response to spectral stimuli, the spectral sensitivity functions of its sensor need to be known. These functions can be determined by direct measurement in the lab-a difficult and lengthy procedure-or through simple statistical inference. Statistical inference methods are based on the observation that when a camera responds linearly to spectral st...

متن کامل

منابع من

با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید


عنوان ژورنال:
پژوهش های علوم و فناوری چوب و جنگل

جلد ۱۶، شماره ۲، صفحات ۱۰۱-۱۲۰

کلمات کلیدی

میزبانی شده توسط پلتفرم ابری doprax.com

copyright © 2015-2023