Analysis of Analysis of S’COOL Data: S’COOL Data:

An An Introductory Introductory

TutorialTutorial

Analysis of Analysis of S’COOL Data: S’COOL Data:

An An Introductory Introductory

TutorialTutorialhttp://scool.larc.nasa.govhttp://scool.larc.nasa.govhttp://scool.larc.nasa.govhttp://scool.larc.nasa.gov

National Aeronautics and Space Administration

www.nasa.gov

FindingFinding the the DataDataUnder thefirst cloud,

SelectStep 4:Database

Selecting Selecting the datathe data

1. Interact with the dataa) Just

yoursb) All

OR…

1. Interact with the dataa) Just

yoursb) All

OR…

Selecting Selecting the datathe data

2. Download all S’COOL and CERES matches (as of Aug. 2004)

2. Download all S’COOL and CERES matches (as of Aug. 2004)

Selecting Selecting the datathe data

3. Get ideas for data analysis

a) This tutorial

b) Excel file 1

c) Excel file 2

3. Get ideas for data analysis

a) This tutorial

b) Excel file 1

c) Excel file 2

Review Review the the ResultsResults4. Read our

analysis of the S’COOL and CERES data-We will be happy to post results of student studies here too!

4. Read our analysis of the S’COOL and CERES data-We will be happy to post results of student studies here too!

Search Search OptionsOptions

• Choose a date range

And/OrAnd/Or• Choose a lat/long region

And/OrAnd/Or• Choose a country

And/OrAnd/Or• Choose results with satellite data

Submit Submit Query Query RequestRequest

• Hit Submit when ready

It may take a few minutes to process the search.

Search Results - Ground OnlySearch Results - Ground Only

The student report

A graphic representation

Search Results - Ground + Search Results - Ground + SatelliteSatelliteA No Cloud CaseA No Cloud CaseThe student report

Excellent Excellent Agreement!Agreement!

The satellite report

Search Results - Ground + Search Results - Ground + SatelliteSatellite

• Of course, the reports from the ground and the satellite may not always agree

• The next few slides illustrate a few examples– Sometimes the disagreement makes sense– Sometimes the disagreement does not make sense

• You can look at your own observations to– Quantify the agreement– Find and further study cases that don’t make sense

• Of course, the reports from the ground and the satellite may not always agree

• The next few slides illustrate a few examples– Sometimes the disagreement makes sense– Sometimes the disagreement does not make sense

• You can look at your own observations to– Quantify the agreement– Find and further study cases that don’t make sense

Search Results - Ground + Search Results - Ground + SatelliteSatelliteCloudy Case - ICloudy Case - IThe student report

The satellite report

Very good Very good Agreement!Agreement!

Only opacityOnly opacity

(a subjective (a subjective measure from measure from the ground) the ground) does not matchdoes not match

Search Results - Ground + Search Results - Ground + SatelliteSatelliteCloudy Case - IICloudy Case - IIThe student report

Near Near disagreementdisagreement

Cloud Cover Cloud Cover differs by one differs by one category. May category. May be off only a be off only a few percent.few percent.

The satellite report

Search Results - Ground + Search Results - Ground + SatelliteSatelliteCloudy Case - IIICloudy Case - IIIThe The student student reportreport

Interesting Interesting disagreementdisagreement

Satellite cannot Satellite cannot see clouds under see clouds under opaque top layeropaque top layer

The satellite reportThe satellite report

Search Results - Ground + Search Results - Ground + SatelliteSatelliteCloudy Case - IVCloudy Case - IVThe student report

Interesting Interesting disagreementdisagreement

Satellite cannot Satellite cannot detect sparse, detect sparse, thin, high cloudsthin, high clouds

The satellite report

Search Results - Ground + Search Results - Ground + SatelliteSatelliteCloudy Case - VCloudy Case - VThe student report

Puzzling Puzzling disagreementdisagreement

Student comments Student comments indicate extensive indicate extensive cloudinesscloudiness

The satellite report

Analyzing the Data - Cloud CoverAnalyzing the Data - Cloud Cover

• So far we have talked about 6 cases (no cloud case, and cloudy cases I, II, III, IV, and V). How could we summarize these?

Low cloudLow cloud Mid-level cloudMid-level cloud High cloudHigh cloud AllAll

Grd Sat

0 0 0 0 PC Cl PC 0 0 0 PC 0

Grd Sat

0 0 MC MC 0 0 PC 0 0 0 0 0

Grd Sat

0 0 PC PC 0 0 PC Ov Cl 0 0 0

3/63/6

50%50%

5/65/6

83%83%

4/64/6

67%67%

2/62/6

33%33%

Grd Ground

Sat Satellite

0 No Cloud

Cl Clear

PC Partly Cloudy

MC Mostly Cloudy

OV Overcast

Analyzing the Data - Cloud CoverAnalyzing the Data - Cloud Cover

Low cloudLow cloud Mid-level cloudMid-level cloud High cloudHigh cloud AllAll

Grd Sat

0 0 0 0 PC Cl PC 0 0 0 PC 0

Grd Sat

0 0 MC MC 0 0 PC 0 0 0 0 0

Grd Sat

0 0 PC PC 0 0 PC Ov Cl 0 0 0

3/63/6

50%50%

5/65/6

83%83%

4/64/6

67%67%

2/62/6

33%33%

Grd Ground

Sat Satellite

0 No Cloud

Cl Clear

PC Partly Cloudy

MC Mostly Cloudy

OV Overcast

Cloud Cover is important to understanding the Earth’s Energy Budget, since clouds both reflect sunlight and modulate emission of heat from the Earth.

Analyzing the Data - Cloud CoverAnalyzing the Data - Cloud Cover

• What if we look at total cloud cover (Low + Mid + High)?-Need to decide how to combine levels - do they overlap?-Use a middle value for ground classes (i.e., 5-50 = 27.5%)

• What if we look at total cloud cover (Low + Mid + High)?-Need to decide how to combine levels - do they overlap?-Use a middle value for ground classes (i.e., 5-50 = 27.5%)

Case Grd* (%) Sat* (%)

1 0. 0. 2 PC+MC = 100. 100. 3 PC = 27.5 2.35 4 PC+PC+PC=82.5 100. 5 Cl = 2.5 0 6 PC = 27.5 0

**No overlap assumedNo overlap assumed

Grd Ground

Sat Satellite

Cl Clear

PC Partly Cloudy

MC Mostly Cloudy

OV Overcast

Grd Ground

Sat Satellite

0 No Cloud

Cl Clear

PC Partly Cloudy

MC Mostly Cloudy

OV Overcast

Analyzing the Data: How Many Cloud Analyzing the Data: How Many Cloud LayersLayers

GroundGround

ObservationsObservations

Sa

telli

te

Sa

telli

te

Ob

se

rva

tio

ns

Ob

se

rva

tio

ns 0 1 >1

0

1

>1

3/6 = 50% agree completely3/6 = 50% agree completely

3/6 = 50% off by one class3/6 = 50% off by one class

Number of Cloud Layers

Cloud Layers are of particular interest

when comparing the passive satellite view of the Earth

from space with the report of human observers on the ground who can

distinguish different cloud layers and

types.

Analyzing the Data: Which Cloud Analyzing the Data: Which Cloud LevelsLevels

Clr Low Mid LM Hi LH MH LMH

Clr Low

Mid

LM

Hi LH

MH

LMH

Cloud Levels seen from GroundCloud Levels seen from Ground

Clo

ud

Lev

els

seen

fro

m S

atel

lite

Clo

ud

Lev

els

seen

fro

m S

atel

lite

3/6 = 50% agree completely3/6 = 50% agree completely

LM = Low + Mid. etc

Cloud Levels are of interest for the same reason, since

human observers on the ground can distinguish cloud

levels better than the top-level satellite view.

Analyzing the DataAnalyzing the Data• Of course, these 6 correspondences were hand-picked to illustrate interesting comparisons.

• What happens if we look at all the data?• Let’s start with the two-week period (Sept. 1-15, 2002) that includes these examples.

• Of course, these 6 correspondences were hand-picked to illustrate interesting comparisons.

• What happens if we look at all the data?• Let’s start with the two-week period (Sept. 1-15, 2002) that includes these examples.

It also tells you how many data points were found = 245.

At the bottom of the search page, you willfind directions, a key to the file, and a link to get the data.

The Downloaded .bin The Downloaded .bin FileFile• The file you get will have a name like

11301239.grn.bin– Decoding:

•1130 is the date (Nov. 30 in this case) you download the file.

•1239 is a time stamp from when you requested the file

•grn means Ground•.bin was chosen as the extension so that most browsers will automatically download the file when you click on the link

• The file you get will have a name like11301239.grn.bin

– Decoding:•1130 is the date (Nov. 30 in this case) you download the file.

•1239 is a time stamp from when you requested the file

•grn means Ground•.bin was chosen as the extension so that most browsers will automatically download the file when you click on the link

Inside the .bin fileInside the .bin file• The .bin file is an ASCII (text) file.• Each line contains the student report and, if available, the corresponding satellite retrieval information.

• The lines are very long and will wrap in most text editors (see below).

• Fields are tab-separated, so that the file can be imported into a spreadsheet program like Excel.

• The .bin file is an ASCII (text) file.• Each line contains the student report and, if available, the corresponding satellite retrieval information.

• The lines are very long and will wrap in most text editors (see below).

• Fields are tab-separated, so that the file can be imported into a spreadsheet program like Excel.

Importing into ExcelImporting into Excel• There are several ways to import data into

Excel. If you already know how, skip this page.1. Open Excel2. Under the File menu, choose Open3. Find the .bin file you downloaded to your

computer. (you may have to Enable: All Documents in the Open menu)

4. Open the file. A Text Import Wizard should start.

5. Delimited is default. Next.6. Tab is default. Next.7. Finish. File should appear as on next page.

• There are several ways to import data into Excel. If you already know how, skip this page.1. Open Excel2. Under the File menu, choose Open3. Find the .bin file you downloaded to your

computer. (you may have to Enable: All Documents in the Open menu)

4. Open the file. A Text Import Wizard should start.

5. Delimited is default. Next.6. Tab is default. Next.7. Finish. File should appear as on next page.

The file in Excel - IThe file in Excel - I

The key lets you interpret the entries in these columns (see slide 22).

Row 1: Variable Name

Row 2: Units

Row 3: Blank

Row 4…: Data

You may notice other blank lines.These have to dowith line feeds, and can be deleted orignored.

The file in Excel - IIThe file in Excel - II

Scrolling to the right in the file, you will find the satellite entries, or the notation NAY (Not Available Yet)

If the satellite saw no cloud in a level it will be left blank.

Analyzing dataAnalyzing data• Now that you have the file open in Excel, you can save it as an Excel workbook, then do all sorts of analyses.

• See the two Excel files (refer to slide 5) for some examples and ideas

• If you discover anything interesting, share it with the S’COOL Team!

• Now that you have the file open in Excel, you can save it as an Excel workbook, then do all sorts of analyses.

• See the two Excel files (refer to slide 5) for some examples and ideas

• If you discover anything interesting, share it with the S’COOL Team!

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Langley Research Center

Hampton, VA 23681

www.nasa.gov