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UO SRML Solar Calculator Help Table of Contents Introduction The Solar Calculator add-in for Microsoft Excel is a program that operates closely with Excel to provide a variety of functions concerning solar irradiance and other matters related the position of the sun. This program was developed by the University of Oregon Solar Radiation Monitoring Laboratory (UO SRML). The solar position calculation is based on the SOLPOS program—written by the National Renewable Energy Laboratory (NREL)—which, in turn, is based on algorithms first published by Joe Michalsky. In addition, calculations of PV power output and related data are based on NREL's PVWATTS software, which incorporates a PV performance model developed at Sandia National Laboratories. For information about obtaining the SRML Solar Calculator software, please contact us. About this program release (v. 3.0) This release of the Solar Calculator brings the PV calculations into agreement with those of NREL's PVWatts revised program in which a DC rating is multiplied by a computed derate factor to give the AC power output. In addition, this release adds macro functionality that allows the replication of a series of calculations with a single mouse click. Finally, there are several new algorithms for correcting rotating shadowband pyranomoeter data. System requirements The Calculator has been tested with the following Microsoft operating systems: Windows XP, Windows 2000 Professional, Windows NT Workstation 4.0, and Windows 98. It is known to work with Microsoft Excel XP, Excel 2000, and Excel 97. The program may be compatible with certain other system configurations, but these have not been tested by the UO SRML. It is recommended that your computer have a
Web browser installed
on it so that you can conveniently view this help file while using the
Calculator. Either Netscape
Navigator or Microsoft Internet Explorer is compatible. You can use any
other browser to read this file, but the Calculator will not be able
to launch it automatically. Please note that you do not need to have
an Internet connection to your computer: except for a few links, this
help file is self-contained and it resides on your local computer.Installation of the Solar Calculator will
result in the creation of a folder called C:\SRML on your computer,
and the total disk space used will be about 1 megabyte (1 MB). No changes
will be made to the Windows Registry database.There are no other specific system requirements,
but as always, when running an application that does a great deal of
computation, you are best served by a computer with a fast processor
and lots of RAM.Installation If you have not already installed the Solar Calculator, and you have an installation diskette or CD-ROM, here is the procedure:
If you do not have an installation diskette or
CD-ROM,
or if your computer does not have a floppy disk drive or CD-ROM drive,
it is still possible
to install the Calculator. Please contact us for assistance.Uninstalling the Calculator It's simple to uninstall the Calculator: (1) Remove Solar Calculator from Excel's list of Add-Ins, and (2) delete the C:\SRML folder. You can do this in the reverse order, but then Excel will display an error message on your screen. A useful tip Note: whenever you make a change to a setting, it takes effect at once, and it is in effect the next time you use the program. There is no need to explicitly save your work, since this is done for you automatically. This behavior may differ from that of other programs you've used. The Solar Calculator was designed to be easy to use effectively, and it does not interrupt your thought process to ask if you really mean what you're saying. In reality, though, nothing too drastic can
happen. With one exception, the Calculator cannot ever delete or change existing data in your
worksheet. Please note, however, that your worksheet's header row may be altered
by the Calculator. Otherwise, the only things that can change are the particular settings you've
indicated you want to use with the Calculator. And, as you'll see, it's very
easy to create these. The remainder of this help file is devoted to
the details of working with the Calculator.The Main tab This is the screen you see when the Solar Calculator starts up. Here, you select the program settings to use—these are called station profiles—and which algorithms to employ. It is here that you actually run the Solar Calculator. Detailed information about these and additional features follow the example screen below. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Choosing a station profile Station profiles are sets of program parameters that you can create, edit, and delete. Here is where you choose the particular profile to use for the calculations you want to perform. When the Calculator starts up, it attempts to find a station profile that is appropriate for the data in your active worksheet. However, you can override this behavior by selecting a profile from the drop-down list. When you first install the Solar Calculator, the list
contains a number of such station profiles, most of which correspond to
monitoring stations where we collect solar radiation data. (In addition, there may be
some profiles that are meant to be used with TMY2 data.) Using
other features of this software, you can tailor the list to suit your own
purposes. In particular, you can create multiple station profiles for selected
monitoring stations, and each of these profiles can specify parameters
that alter, in some respect, the Calculator's behavior.Note that there is one profile, the Default
Station profile, which does not represent a real monitoring station. This
set of parameters merely exists so that you'll always have at least one
template to use when creating new profiles. Most of the parameters for
this profile can be edited, although the profile itself cannot be deleted.Selecting algorithms The Solar Calculator can perform from one to three calculations simultaneously. Each calculation uses one of about fifty distinct algorithms which you can choose using the three algorithm list boxes on the Main tab. Many of these algorithms yield results deriving from the position of the earth at given times, while others also involve figuring the degree of refraction of the atmosphere, the amount of solar irradiance under various conditions, or PV power output. In the above screen example, you can see that the
two selected calculations have descriptive names preceded by short designations in
square brackets. Each of these codes consists of a category (PV, RAD, GEOM, or
XTRA), followed by a number. They are intended to help you navigate more quickly
through the drop-down lists of calculations.In the PV category are algorithms closely related to
PV, or photovoltaic, applications. The RAD category consists of other algorithms that
concern solar irradiance. GEOM is a large category that groups algorithms that have to
do with computing the apparent position of the sun. Finally, XTRA is a collection of
algorithms that do not fit in the other three categories, or that are probably not
as commonly used as the others. As you'll see when we
discuss the Preferences tab, there is another program feature to help you
organize this list of algorithms (and the list of station profiles).Besides choosing particular algorithms, you can
also specify the header text that Excel will display, respectively, in each
corresponding result column of your worksheet. Initially, these column headers
are set to the (long) names of each of the various algorithms. You'll probably
want to shorten them considerably. The above example screen depicts customized
column headers.While the Calculator is limited to three calculations
at a time, you can perform more by simply repeating the process of
choosing algorithms and clicking the Run button.For your convenience, any selected algorithms
and edited column headers are remembered for you as part of the station profile
you're currently using.Computing with averaged time values versus given time values This program feature may be confusing at first, but it is quite useful. For example, when computing the solar irradiance on a tilted surface, you may be using a data file that contains global, diffuse, and direct normal (beam) measurements averaged over a particular time interval—typically 5, 15, or 60 minutes. However, the time values that are given in the data file generally represent the ending boundaries of these intervals. So, using times mid-way between each of the given points in the data file will more accurately model the circumstances in which such irradiance measurements are valid. In such cases, you should select the Average with preceding times option. On the other hand, if you select the Use given
time option, all computations will be done as if the inputs (solar irradiance
values, air pressure, etc.) are those that were in effect at the exact times
found in the data file. This option is perfectly valid if you are generating
results that have to do only with the earth's position at a given time, and not
with any other measured, averaged input data.For your convenience, the option you choose here
is remembered for you as part of the station profile you're currently using.About data file column names Near the bottom of the Main tab is a check-box labeled Use English source column headers. When a check mark appears in this box (the default setting), you'll notice that certain worksheet column headers consist of descriptive English words, abbreviations and numbers. In addition, you'll find that the same sorts of names occur in various drop-down list boxes on the Calculator form. These names will usually suffice to convey the actual type of data found in corresponding worksheet columns. Normally, you should leave this program feature in its default
state. If you click the box to remove the check mark, all the mnemonic names (in the worksheet
and in the Calculator form) will be replaced by
4-digit numbers. These numbers are used at the UO Solar Radiation Monitoring Lab when processing
data files automatically. No harm should come from repeatedly clicking this check-box. However,
keep in mind that the format that is active when you quit the Calculator will be in effect for
your data file.The Run button The Run button does just what you'd expect: it causes the Calculator to perform the calculations you've selected. However, prior to this, your active Excel worksheet is checked for data that might cause problems during the calculations. As well, the options and parameters you've specified on the Calculator form are checked for consistency and completeness. Consequently, just after clicking this button, you may see a message on the screen informing you of a potential problem that needs to be addressed before the calculations can take place. The Return to Excel button Clicking the Return to Excel button closes the Calculator program and allows you to perform any other Excel functions you choose. Unfortunately, you cannot access your worksheet or
any general features of Excel while the Calculator is running. This is characteristic of all
Excel add-in applications that are compatible with Excel 97. However, you may quit
the Calculator at any time, and when you next run it, you'll find that all the
settings are just as you left them.The Help button and context-sensitive help Clicking the Help button causes your Web browser to open this help document. Notice that this button appears on each tab, or page, of the Calculator's form. The particular section of this file that you'll see first depends on the Calculator tab that is active when you click the button. Please note that context-sensitive help is available for nearly all features of the Calculator program. To use it, position your mouse cursor on a feature, then right-click to see the What's this? menu item nearby. Click this menu item to navigate directly to documentation in this file that concerns the program feature you've selected. The Station profile tab This screen contains the basic parameter settings that define a station profile, including its location and information about certain data file columns. This is where some of the customizing of station profiles is done, and it's where you can create new ones or delete unneeded ones. Detailed information concerning features on this tab follows the example screen below. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Basic station profile parameters At the top of the screen, there is a set of four important parameter settings: Latitude, Longitude, Time zone, and Station code. Latitude and longitude are in (decimal) degrees, with southern latitudes and western longitudes expressed as negative values. Time zones are negative offsets from Universal Time Code (UTC) west of Greenwich. If you have incorrect values in any of these fields, the Calculator will not generate the results you desire. The station code is, by the UO SRML convention,
a 5-digit number that corresponds to a particular physical monitoring
station. In the National Solar Radiation Data Base, these values correspond
to WBAN numbers. Such codes also occur in our data files, and the Calculator uses the
code value to determine which station profile to load initially. Specifically,
the Calculator loads the profile that is first in alphabetical order
among any whose station code matches the one in the worksheet. If no match is
found, the Default Station profile is loaded. We have included a list of
these codes near the end of this help document.Selecting a source for air pressure Air pressure is one of the inputs to about a dozen algorithms which involve atmospheric refraction. As you can see, there are several ways to specify it: as actual measured data values (in millibars) in a particular worksheet column, as a default value in millibars, or as a derived value that is calculated from altitude in meters. The default value is also used whenever an air pressure value in the worksheet is bad (flagged "99"). Selecting a source for temperature Temperature is another input that is used for calculating refraction. It also has an effect on PV performance calculations. It can be read from a given column (of Celsius data) in the Excel worksheet. Alternatively, it can be specified as a default Celsius value. The default value is also used whenever a temperature value in the worksheet is bad (flagged "99"). Selecting a source for wind speed Like some of the other settings, wind speed can be specified as a default value, or as data to be gotten from a particular worksheet column. Wind speed, which should be in meters per second, is used by the Calculator in modeling the performance of PV cells. If the wind speed value in a particular row of your worksheet is bad (flagged "99"), then the default value is assumed. Selecting a source for year The Solar Calculator always needs specific dates and times to determine the location of the sun—or, according to Copernicus, the earth. These values are taken from the first two columns of your active Excel worksheet. However, the year portion of the date is normally found in the second column of the worksheet header, in which case it is global to the worksheet, understood to be the year in which all dates and times occur. For all typical UO SRML data files, you should then specify the File header option. In
the case of worksheet data we derive from TMY2
files, each month block of data values may occur in a different year. Consequently,
the Calculator cannot apply a single year value to the entire worksheet; instead,
the year must be in a column of its own. For TMY2 data, you should select the
'Year' column option. Note: If Use English source column headers is not
checked (active) on the Main tab, this option will read '8888' column.
If you have questions about using TMY2
data with the Solar Calculator, please contact us.Creating a new station profile The way to create a new station profile is to copy an existing one, then edit the copy. Choose a profile that is most like the one you want to create, then click the New profile button. You'll be asked to enter a name for the new profile, and this must be unique. You may find it helpful to choose a name corresponding to the specific parameter settings in the profile. For example, you might incorporate the tilt angle or an irradiance column header in the name. Important: Remember that any changes you
make to a profile take place immediately. Therefore, unless you really want to
edit an existing profile, you should click the New profile button
first, editing only the new copy.Deleting a station profile When you click the Delete profile button, the currently loaded profile is immediately deleted. The Calculator then attempts to find another profile whose station code matches the one in your Excel worksheet. If more than one exists, it will load the one that is next, alphabetically; if none exist, it will load the Default Station profile. The Delete profile function is provided
so that you can dispose of experimental profiles or those that are just used
temporarily. However, the Calculator allows you to have as many profiles as you want—well,
tens of thousands, anyhow. Consequently, you really don't need to
delete any of them. As you'll see further below, there is another way to
avoid having to select a profile from a very crowded list.The Profile (part 2) tab This screen supplements the Station profile tab with parameter settings that are required for real-world applications of solar irradiance data. At present, such uses involve PV array performance and modeling of direct normal (beam) irradiance. In the future, the Calculator may support other application areas, such as daylighting and solar water heating. Detailed information concerning features on this tab follows the example screen below. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Entering tilt parameters Tilt, in degrees, describes the angle formed by a surface with respect to the plane that is tangent to the earth's surface at its location. Aspect, also in degrees, describes the direction of the tilted surface, with zero being due north, 90 due east, 180 due south, and 270 due west. Note:
tilt and aspect settings here must agree with
those implied for any measured tilted irradiance values specified on the right side of this tab.
In other words,
if you set Tilt to 30° and Aspect to
180°, the selected tilted irradiance column (if any) in the list under the Use tilted measurements
option must contain data that have been measured by a device with this
same tilt and aspect. Failure to insure this consistency will lead to erroneous results.Entering PV array parameters Obviously, PV array settings are used for modeling the output of PV arrays. There are three types of arrays to choose among: fixed, 1-axis, and 2-axis. In addition, you specify the DC power rating of the array, and, to see how much money might be saved (on electric bills, at least), you can specify the energy cost in cents per kilowatt-hour. Notice
the non-editable text on the example screen that states the Derate factor. You can set the
value of this factor on the Derate tab, but its value is displayed here as well because it
is related to PV applications. The derate factor is used to derive the expected AC power output
from the DC power rating.Note:
Tilted surface settings must specify the tilt
and orientation (aspect) of the array. In case you are modeling multiple arrays of various
power ratings and tilts, you can break the calculations up into stages and then, using normal
Excel functionality, sum the individual array results.Selecting sources for irradiance data The Calculator requires irradiance inputs for certain calculations. Here you can specify, first, whether actual tilted irradiance data should be used, or whether the Calculator should derive or model tilted irradiance based on global horizontal, direct normal, and diffuse input values. Once you select one of the options Derive tilted irradiance or Use tilted measurements, you must then select the actual column or columns in your worksheet that contain these data. Although you can specify any of the list values,
calculations using irradiance data will not be performed unless corresponding
columns actually exist
in your active Excel worksheet. The Calculator only checks for this at the moment you
click the Run button, so you can configure settings for
station profiles that will not be used immediately. (This is also true of all columns you
select on the Station profile tab.)Using a calibration factor This feature is probably mainly of interest to the staff at the UO SRML. When you specify a calibration factor, you can then select one of the three calibration algorithms from the Main tab. These algorithms use the calibration factor to multiply the selected global, diffuse, or direct beam irradiance value. Of course, this kind of functionality is easily obtained from Excel. However, by allowing the user to perform these kinds of calculations from within the Solar Calculator, certain processes can be automated via the Calculator's macro facility. Selecting a source for albedo Albedo, or ground reflectivity, is only used by the Calculator to model tilted irradiance. Note that the second option, Snow cover column, should be selected if your worksheet contains TMY2 data. The Default option should be used if neither measured albedo nor snow cover data are available. A value of 0.2 is typically assumed for the types of calculations this software performs. The Derate tab This screen contains parameters which are multiplied together to compute a derate factor which is then used in computing AC power output. Alternatively, an arbitrary derate factor may be entered without computing it first. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Entering derate parameters Note: We wish to thank the National Renewable Energy Laboratory, whose own documentation was closely adhered to in preparing the remarks below. Of course, we are indebted to NREL, as well, for many of the algorithms implemented in this software. Each of the individual factors that contribute to the overall derate factor has a permissible range and default value as depicted in the screen image above. Here is a brief summary explaining what each of these factors is meant to model:
The Preferences tab This screen contains features that do not pertain to a single station profile, but are more global in scope. Here you can determine which station profiles and which algorithms you want to see in the selection lists on the Main tab. As well, you can set the size of the Solar Calculator screen to best match your monitor's dimensions and pixel resolution. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Setting station and algorithm preferences The two lists provide a means to specify which station profiles and which algorithm types will be active; i.e., selectable in the pull-down lists on the Main tab. This is fairly straight-forward, but there is one side-effect that should be noted: Only active station profiles are loaded automatically. This allows you to determine which profile—among possibly several having identical station codes— gets loaded when a particular station code appears in your Excel worksheet. Otherwise, it is always the one that is first in alphabetical order. Setting the Calculator window size Use this feature to adjust the Calculator's window size so that you can comfortably read all the text and manipulate all the controls. Clicking the up-arrow increases the window size; clicking the down arrow decreases it. The size percentage relative to a default setting is displayed to the right of these arrows. You cannot directly enter a percent value in the text box. Note that, due to the way Excel deals with screen fonts, some size settings will result in truncated labels or unintentional boldface text. If you experiment a bit with different settings, you'll be able to find one that works for your computer. Like all the Calculator's settings, your choice of window size is remembered for you until you change it. Types of calculations Each of the currently provided algorithm types are listed below:
The Macros tab This screen contains settings that allow you to have your key strokes and mouse clicks saved and then recalled later on and repeated automatically. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Selecting a macro The drop-down list contains the names of any macros you have previously defined. You must select one from the list in order to either run it or delete it. In the screen image above, no macro is currently selected. Once you've chosen a macro, click the Run Macro button to execute it. The Solar Calculator will repeat all the previously recorded key strokes and mouse clicks that comprise the selected macro. If you don't think you'll use a particular macro again, select it and then click the Delete Macro button. It will be removed from the selection list. Recording a macro To record a new macro, first key in a unique name. This will be the name that appears in the drop-down selection list above. Next, click the Record Macro button. Now you can begin using the Calculator as you normally do: change settings, select calculations, etc. When you have finished with the series of steps that you wish to record, return to this tab and click the End Recording button. Note that quitting the Calculator at any point during the recording process will in effect end the recording. Data file format requirements This brief discussion will refer to the graphic example directly below. In the example, we see one of the UO SRML's data files—a Eugene 5-minute data file. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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In the header row of the worksheet, there are several points to note: the station code appears in cell A1, the year in cell B1, and succeeding columns alternately contain a data type code or the character zero. The latter indicates that the column contains a data quality flag. (The UO SRML Web site contains documentation about station codes, data element numbers, and quality flags.) Data quality flags are used by the Solar Calculator, for
certain computations, to determine whether to base calculations on actual data from
worksheet columns, or on default values either specified
in the station profile or furnished by the Calculator. Default values are used when
flags indicate that respective data is unreliable. Note that when the Calculator
computes certain new values (such as direct normal irradiance), it also generates an
additional corresponding
flag column with values pertaining to the resulting calculation.The example worksheet shows a number of columns for
irradiance data: several for global and one for direct normal (beam). In addition,
we see that column A contains the yearday, and column B
specifies the time. Time is specified in the 24-hour format where 100 is
1:00 am, and 2400 is midnight. This example is shows only the left-most columns of
the file; other columns that are not visible here contain diffuse irradiance data
and various meterological data.The Calculator handles data files having the most
commonly used time intervals: 5-minute, 15-minute, and hourly. Prior to executing
the algorithms you select, the dates and times are checked for validity and
consistency. If there is a time or date gap (or a repeated date and time) in your
worksheet, the Calculator will
notify you with a warning that results may be incorrect. Note, however, that in
TMY2 data files, there will usually be at least one such gap or repeated interval.
But, because any discontinuities occur at midnight in these files, calculations
concerning PV performance are unaffected.If you only need to compute certain
geometrical results, such as sunrise and sunset times, you could
use a worksheet containing just two columns, with the station code and year in
the header row, and yeardays and times below. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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SRML numeric data element codes If you are working with files from our Web site, and you do not have the Use English column headers option checked on the Calculator's Main tab, your Excel worksheet's header row and the contents of various drop-down list boxes on the Calculator form will appear as 4-digit data element codes. The tables below list these codes along with short descriptions.
SRML data quality flags Data quality flags accompany most of the data columns in SRML files. These appear in columns directly to the right of the actual data to which they correspond, and they have the number zero in their header row. They are used for quality control, and to indicate whether, or how, the data were processed. The following table provides an explanation for each of our two-digit flags:
Notes Flag 13. Data flagged 13 is not reliable for use in developing models. Often data is flagged 13 if it might have something wrong. For example, it's not always possible to discern the precise time when an Eppley NIP goes out of alignment. If the NIP is known to be out of alignment on a particular day, then the direct normal data for the previous day may be flagged 13. Flag 23. Data are corrected only if we can be reasonably sure of the correction, and if the resulting values are within 5% of the actual values. For example, if snow is building up on a pyranometer during the first part of the day, and the direct beam measurements show that there were few—if—any clouds, it is sometimes possible to correct the global values. Any values that are manually changed from the original data are flagged 23. SRML station ID codes The Solar Calculator relies on a 5-digit number in cell A1 of the active Excel worksheet to initially determine which station profile to load. For your own data files, we recommend that you avoid using any codes that have historically been associated with SRML stations. The following table lists most of these, though we add new ones from time to time. The table also provides a standard 2-character identifier for each station; we use these in naming our data files. Please note that some of the monitoring stations listed are not currently in service, and certain others are privately operated, requiring that special permission be obtained to use data gathered there.
 © 2004, UO Solar Radiation Monitoring Laboratory. Last
revised: January 21, 2004.Home page URL: solardat.uoregon.edu | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||