Delta Electronics SS1-UM-1.05 user manual Modelling incomplete PAR absorption and scattering

Page 61

This was again calculated numerically and curves fitted to the data with similar accuracy as above. The curves fitted are:

 

Given:

 

 

 

 

 

P ( x )

 

1

 

 

 

 

0.4.exp( 0.1. x ).( atan( 0.9.x )

 

0.95 )

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q( x )

 

 

0.255. atan( x )

 

 

 

0.6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R( x )

 

 

exp(

 

x )

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P ( x ). LQ( x)

 

 

 

 

R( x ). ln( 1

 

 

 

 

L )

 

τ

spher

( x , L )

 

exp

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Diffuse light transmission (hemispherical response sensor)

 

Transmission

1

 

 

 

 

 

 

fraction

 

 

 

 

 

 

Leaf Angle

 

 

 

 

 

 

 

Distribution

 

 

 

 

Vertical

 

 

 

 

0.1

 

 

 

 

 

τ spher ( 0 , L )

 

 

 

 

 

Vertical

 

 

 

 

 

 

Spherical

τ spher ( 1 , L )

 

 

 

 

 

 

Horizontal

τ spher ( 1000 , L )

0.01

 

 

Spherical

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Horizontal

 

 

 

0.001

2

4

6

8

10

 

 

0

L Leaf Area Index

Modelling incomplete PAR absorption and scattering

Radiation models have been used for many years to calculate the effects of scattering in the canopy e.g. Norman & Jarvis (1975). Wood's model incorporates Campbell’s ellipsoidal leaf angle distribution and the effects this has on transmission of both Direct and Diffuse light.

The model splits the canopy into layers of LAI 0.1, extending to a sufficient depth to absorb all of the incident light. Incident light above the top layer was a known fraction of Direct (at a given zenith angle) and Diffuse light. The amount of light absorbed by a layer, assuming completely black leaves, was calculated. The fraction of this absorbed light re-emitted by the leaves was then assumed to be re-emitted in all directions uniformly (see Monteith & Unsworth, 1990, p85 onwards) .

The light level at any point in the canopy is then the light calculated assuming complete absorption, plus the sum of the light re-emitted by each canopy layer, attenuated by the intervening layers.

These calculations had to take full account of both horizontal and vertical light components. This involved an iterative solution and a lot of computer time. Finally, the light intensity as measured by a cosine corrected sensor was calculated.

SunScan User Manual v 1.05

LAI theory • 61

Page 60 Page 62
Image 61
Page 60 Page 62
Contents SS1-UM-1.05 SunScanAcknowledgements CopyrightTrademarks CE conformityContents Measurement options Menus and Screens More Psion and file handling notesLAI theory Technical Reference sectionIndex AppendicesIntroduction How to use the manualsSunScan Canopy Analysis System Organisation of this manualSunScan probe Field accessoriesBeam Fraction sensor Data Collection TerminalPreliminary checks Getting StartedWorkabout and SunScan probe Checking the Workabout hardware Installing the s/w Installing the SunData s/w in your PCSunData s/w Diskette What the s/w doesRunning SunData Setting up your PCs COM portSunScan probe to PC Communication checksWorkabout to PC Running SunData in Windows About this tutorial SunScan TutorialWorking with the Workabout Starting SunData in the Workabout What to do if you get lostStarting the PC software Using a PC instead of the WorkaboutThis page is intentionally blank Working through the menu options Setting up a measurement sessionHot Keys File SavingTaking readings Using the Emulator modeWithout a Beam Fraction Sensor Connecting the SunScan probeConnecting the Beam Fraction Sensor Measuring Leaf Area Index without a Beam Fraction Sensor Averages Reviewing your data fileFrom the Workabout Transferring the data file to your PCTo the PC Initiating the file transfer from the Workabout Meanwhile, on the PC Conclusion of the Tutorial RS232 communication problemsSunData Screens on the Workabout Menus and Screens SettingsFile Utils ContdQuit Navigating Psion directories and screens More Psion and file handling notesWorkabout User Guide Navigating the Psion directories and screensPsion subdirectory usage in file select dialogs Deleting unwanted Workabout files Re-installing the SunData application iconFlashcards reformatting SunData Configuration files Configuration and data file handlingData memory management Creating a configuration file Default .cfgRestoring a configuration Data files.PRN file Displaying data files on your PC.CSV file Data file layouts and data groups Page Experiment design Measurement optionsAbove-canopy reference requirements Canopy type and BFS practicalities Canopy Sampling volumeCanopy type and LAI estimates Planning for the sun’s position Preferred light and weather conditionsSetting Eladp Advice on Absorption and Eladp valuesAbsorption Estimating Eladp in the field Relationship between Mean Leaf Angle and EladpSunScan System Measurement modes Workabout setupLAI, PAR and All displays Autolog function Probe handling in the field Measurement procedures in the fieldProbe GO button Levelling the probeBFS handling in the field Using the tripodUse of the tripod WorkaboutLevelling the BFS Finding North, and setting the shade ringExtension cables, and the location of the BFS Factory light calibration PAR calibrationsChecking the probe/BFS matching Recalibrate optionRestoring the factory calibration Routine maintenance and cleaningEffect of the shade ring on the BFS Comparing the calibration with other PAR sensorsSunScan probe and Beam Fraction Sensor Environmental and moisture protectionIngredients of the LAI computation method LAI theoryMajor assumptions Derivation of Wood’s SunScan canopy analysis equationsTheory versus reality Campbells Ellipsoidal LAD equations Beers law for canopy absorptionTransmission of Diffuse Light Transmission fraction τ Is given by I/I0 Diffuse light transmission cosine corrected sensor Modelling the canopy transmissionDetail Accuracy of LAI calculations Functions used to model canopy transmissionDiffuse light cosine response sensor Diffuse light hemispherical response sensorExp 0.1 . x . atan 0.9 Atan L Q Spher Modelling incomplete PAR absorption and scatteringCalculating zenith angles Scientific referencesSummary Jones, Hamlyn G Plants and Microclimate second edition. CUP Technical Reference section Maintenance and repairChecking the batteries SunScan probe batteriesChecking the desiccant Checking the PAR calibration Re-setting the factory calibrationFactory calibration method Problems running the SunData application TroubleshootingPsion Workabout While running SunDataInsufficient power to write data reported Technical Support SunScan Probe Type SS1 SpecificationsBeam Fraction Sensor type BF1 Data Collection Terminal type DCT1 Psion WorkaboutTelescopic Tripod type BFT1 Carrying Case type SCC1Spares Kit type SPS1 Logging CablesSpectral response PAR PerformanceSunScan system cosine response Cosine responses of probe and BFSLogging the probe as a Linear Quantum Sensor AppendicesLogging the Beam Fraction sensor SunData PC s/w Upgrading the SunScan systemWorkabout SunData s/w Revision HistoryChoice of different programs File transfer between Workabout and PCPsiWin Workabout Remote LinkSlink and Rcom Example using SlinkDrives on the PC are referred to as REMA, Remc REM = remote Documentation of Rcom and Slink Example using RcomAlternative file transfer mechanisms Using the Workabout Comms applicationSending a file to a Communication program Sending a file to a serial printerGlossary Page Accuracy IndexIndex Field use 39, 46, 48, 50, 51, 58

SS1-UM-1.05 specifications

Delta Electronics has long been recognized for its innovative solutions in power and thermal management technologies. One of its notable products is the SS1-UM-1.05, a compact and efficient power supply module designed to meet the needs of a variety of applications, from industrial automation to telecommunications.

The Delta SS1-UM-1.05 is a key component in the company’s extensive portfolio, providing reliable and stable power supply for both demanding and sensitive electronic equipment. One of the main features of this module is its high efficiency, which typically exceeds 90%. This not only minimizes energy consumption but also reduces heat generation, making it an ideal choice for applications where thermal management is crucial.

Another significant characteristic of the SS1-UM-1.05 is its wide input voltage range, which allows it to operate effectively in various environments. The module supports a voltage range from 90 to 264 VAC, ensuring consistent performance even in fluctuating supply conditions. This versatility makes it well-suited for global applications, accommodating different electrical standards and requirements.

The SS1-UM-1.05 also boasts a compact footprint, which is essential for space-constrained installations. Its design emphasizes not only performance but also ease of integration into existing systems. The module provides multiple output voltage options, allowing it to cater to specific power requirements, whether it be for industrial machinery or consumer electronics.

In terms of technologies, the SS1-UM-1.05 incorporates advanced power conversion technologies that enhance its overall performance. It features overload protection and thermal shutdown mechanisms to safeguard both the module and the equipment it powers from potential damages due to electrical faults. Moreover, it has low electromagnetic interference (EMI) emissions, which is crucial for environments sensitive to electrical noise.

The SS1-UM-1.05 is also designed with a robust enclosure that adheres to stringent safety and environmental standards. This enhances its durability and reliability, ensuring it can withstand harsh operating conditions. With these features, Delta Electronics demonstrates its commitment to delivering high-quality products that meet the evolving needs of industries worldwide.

Overall, the Delta SS1-UM-1.05 power supply module is an exemplary solution for those seeking a reliable, efficient, and compact power source. Its advanced features and technologies make it an indispensable component in modern electronic systems.
Top Page Image Contents