1 enviromatics 2008 - environmental sampling environmental sampling Вонр. проф. д-р...

1Enviromatics 2008 - Environmental sampling

Environmental sampling

Вонр. проф. д-р Александар Маркоски

Технички факултет – Битола

2008 год.


Definition

• Environmental sampling is defined as an observation of changing environmental states.

• Environmental monitoring is defined as a continuous automated observation of environmental states.

• The goal of sampling is information mining about the frequency distribution of environmental data or about their probability distribution parameters.


Introduction

• Ecological data are obtained by field samples and/or laboratory analysis. They are directly observed (direct observations) or indirectly observed (due to calibration of analytical instruments and sensors). Summary data are derived from statistics or by restricted observable indicators. Simulated data are obtained by simulation models.

Recommendations for environmental sampling • The goals and needs for environmental data collection

should be formulated explicitly for each application. Prior knowledge of the factors that effect environmental variables to be sampled should be given. During sampling significant changes of external and internal driving forces should not be take place. Existing estimates may be sufficient if they were obtained by unbiased sampling design.


Sampling design

Phases of data flow in environmental sampling are given by • data capture (e.g. observation, measuring, description), • data processing (e.g. aggregation, identification, statistics), • data storage (e.g. data bases, metadata, GIS), and • data analysis (modelling, simulation, decision support

systems, knowledge systems).

For sampling design basic knowledge on environmental processes should be given.


Sampling design (2)

• A prerequisite for process or system identification is the availability of appropriate records of the observed process or system dynamics.

• Important aspects of experimental design are

1. major process time-constants,

2. sampling (measurement) frequency,

3. duration of observations and experiment,

4. choice of initial (start) values of observations,

5. noise level, and

6. process nonlinearities.


Examples for sampling of environmental variables

1. Water budget: Surface and groundwater inputs, outputs and changes;

2. Chemical variables: Organic and inorganic substances, metabolites;

3. Physical variables: External and internal driving forces;

4. Biological variables: Uptake and conversion of nutrients and organic substances by plants and animals;

5. Other variables as required.


Essentials for sampling of environmental data• Information content of data: Observation, recording of data and/or

monitoring of the environmental states characterized by chemical variables.

• Description of data: Data analysis, statistical, chemometrical and cause-effect modelling and simulation.

• Technological design: Development of sampling and application of application of modern detection methods for environmental constituents, laboratory equipments, hardware and software.

• Space and time design: Consideration of space domain of scaling and time depending changes of processes and their rates, change of the environmental states by internal and external control schemes.

• Institutional design: Administration and organisation of environmental management,balancing of resources, hierarchy of environmental control activities.

• Economical design: Characterization and evaluation of management alternativesand their environmental effects, decision and policy making.


Sources of variability in sampling programs

Sources of variability in sampling programs are given by • the variability caused by environmental factors (between

sites and dates,or between dates at the same sites),• the variability caused by intrinsic factors between samples

(same site and same date),• the variability caused by different chemical analytical

methods (between determination), and• the variability caused by different chemical pre-treatments

(same determinations).


Satellite imagery

• Digital raster data obtained from satellite systems contain the environmental information in an implicit form only. The same areas are never recorded in the same way because of the changing conditions of the atmosphere, vegetation and their illumination. For this reason, a developed branch of engineering exists to analyse this kind of imagery.

• It involves techniques from different engineering and scientific disciplines e.g. control engineering, civil engineering, process engineering, electrical engineering, information technology, computer technology, mathematics, informatics, chemistry, biology, ecology, where methods of signal processing, statistics, pattern recognition and artificial intelligence are included.

• Problems are caused by classifying of pixels, by grouping of adjacent pixels to form objects, by identifying patterns of images of the real world, and by the recognition of features..


Landsat

• Landsat provides periodic high resolution multi-spectral data of the Earth’s surface on a global basis. Landsat orbits the earth once every 16 days, taking pictures of each part of the surface of the Earth. Each scene covers an area of 185 by 172 km².


Example 1


SPOT

• SPOT (Satellite pour l’observation de la terre) is an Earth observing satellite. SPOT features some sophisticated scanning technology to support stereoscopic imagery and other advanced viewing options. Main applications include environmental impact studies, geologic exploration, and thematic map making.


AVHRR

• AVHRR (Advanced Very High Resolution Radiometer) is satellite system applied to weather forecasting, pollution monitoring, toxic algal bloom detection, and sandstorm monitoring. It is also used to map global vegetation. The U.S. Geological Survey’s Data Centre produces four level of data products of AVHRR time series that designed for both biophysical and land cover data requirements of global change research.


Questions?

1 enviromatics 2008 - environmental sampling environmental sampling Вонр. проф. д-р...

Documents

environmental data collection

environmental monitoring

environmental processes

environmental constituents

description of data

introductionecological

data bases

data storage