MIST Data Summaries

Overview

The MODIS Interactive Subsetting Tool (MIST) provides subsets of certain Version 5 (V005) MODIS products, over the Greenland Climate Network (GC-Net) and the International Arctic Systems for Observing the Atmosphere (IASOA) stations. Data are provided in a text Comma Separated Value (CSV) file format, courtesy of the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC). Refer to Table 1 for a list of the MODIS products supported by MIST.

Note: To obtain documentation for a particular data set, click on the Long Name in Table 1.

Table 1. MODIS Products Supported by MIST

Short Name	Long Name	Temporal Coverage
MOD09A1	MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid	2000-02-24 to present
MOD10A1	MODIS/Terra Snow Cover Daily L3 Global 500m Grid	2000-02-24 to present
MOD11A2	MODIS/Terra Land Surface Temperature/Emissivity 8 Day L3 Global	2000-03-05 to present
MCD43A1	MODIS/Terra+Aqua BRDF/Albedo Model Parameters 16-Day L3 Global 500m SIN Grid	2000-02-24 to present
MCD43A2	MODIS/Terra+Aqua BRDF/Model Quality 16-Day L3 Global 500m SIN Grid	2000-02-24 to present
MCD43A4	MODIS/Terra+Aqua Nadir BRDF-Adjusted Reflectance 16-Day L3 Global 500m SIN Grid	2000-02-24 to present

The Stations

The GC-Net and IASOA station's in-situ data correspond to the MODIS data products listed in Table 1. However, we currently do not supply the in-situ station data. When using the subsetting tool, you need to pick a station or stations for the corresponding MODIS data you want to receive.

GC-Net Stations

GC-Net consists of 20 Automatic Weather Stations (AWS) that collect climate information on Greenland's ice sheet. Each AWS is equipped with a number of instruments to sample the following:

• air temperature
• wind speed
• wind direction
• humidity
• pressure
• accumulation rate at high temporal resolution to identify and resolve individual storms
• surface radiation balance in visible and infrared wavelengths
• sensible and latent heat flux fluxes
• snowpack conductive heat fluxes.

Refer to Table 2 for a listing of the station's Identification (ID) Number, the station names, the station's latitude and longitude coordinates, the date when the station became operational, and the the station's Site ID. The Site ID is used in the output CSV file. To order in situ GC-Net data, visit the Greenland Climate Network Data Request Web site.

Table 2. GC-Net Stations

ID #	Name	Latitude	Longitude	Elev.[m]	Start Date	Site ID
1	Swiss Camp	69.5732 N	49.2952 W	1149	1995.00	fn_dkswcamp
2	CP1	69.8819 N	46.9736 W	2022	1995.39	fn_dkandcp1
3	NASA-U	73.8333 N	49.4953 W	2368	1995.41	fn_dkdnasau
4	GITS	77.1433 N	61.0950 W	1887	1995.43	fn_dkndgits
5	Humboldt Gl.	78.5266 N	56.8305 W	1995	1995.47	fn_dkhumbdt
6	Summit	72.5794 N	38.5042 W	3208	1996.37	fn_dksummit
7	Tunu-N	78.0168 N	33.9939 W	2020	1996.38	fn_dkdtunun
8	DYE-2	66.4810 N	46.2800 W	2165	1996.40	fn_dkdye2
9	JAR1	69.4984 N	49.6816 W	962	1996.47	fn_dkjar1
10	Saddle	66.0006 N	44.5014 W	2559	1997.30	fn_dksaddle
11	South Dome	63.1489 N	44.8167 W	2922	1997.31	fn_dksdome
12	NASA-E	75.0000 N	29.9997 W	2631	1997.34	fn_dkdnasae
13	CP2	69.9133 N	46.8547 W	1990	1997.36	fn_dkandcp2
14	NGRIP	75.0998 N	42.3326 W	2950	1997.52	fn_dkdngrip
15	NASA-SE	66.4797 N	42.5002 W	2579	1998.30	fn_dknasase
16	KAR	69.6995 N	32.9998 W	2400	1999.38	fn_dkandkar
17	JAR2	69.4200 N	50.0575 W	568	1999.41	fn_dkjar2
18	KULU	65.7584 N	39.6018 W	878	1999.46	fn_dkndkulu
19	JAR3	69.3954 N	50.3104 W	323	2000.41	fn_dkndjar3
20	Aurora	67.1352 N	47.2911 W	1798	2000.48	fn_dkaurora

IASOA Stations

IASOA is an organization developed to enhance Arctic atmospheric research by fostering collaborations among researchers during the International Polar Year (IPY) and beyond. The science mission is to collect the information necessary to understand the processes and mechanisms of Arctic climate change. The logistical mission is to coordinate measurement programs on atmospheric properties such as:

• precipitation
• atmospheric radiation
• water vapor
• ozone
• aerosols
• chemistry/radio nuclides
• cloud properties
• climate-grade temperature/winds
• snowfall
• surface fluxes between observatories.

Refer to Table 3 for a listing of the member stations, the station's Site ID, and the station's latitude and longitude coordinates. The Site ID is used in the output CSV file. To order in situ IASOA station data, you need to go directly to each site for their data. To find the URLs for each site, visit the IASOA Web site and click on the Observatories link in the left-hand navigation. A link to each specific site is listed on that Web page.

Table 3. IASOA Stations

Latitude	Longitude	Location	Site ID
82.5017 N	62.3297 W	Alert, Canada	fn_caalert2
80.050 N	86.417 W	Eureka, Canada	fn_caeureka
71.323 N	156.609 W	Barrow, USA	fn_usbarrow
71.58 N	128.92 E	Tiksi, Russia	fn_rutiksi1
69 N	161. E	Cherskii, Russia	fn_ruchskii
78.908 N	11.881 E	Ny-Alesund, Norway	fn_nyalesun
67.37 N	26.65 E	Sodankyla, Finland	fn_fisoldpa
67.974 N	24.116 E	Pallas, Finland	fn_fisoldpa
68.35 N	18.82 E	Abisko, Sweden	Not Applicable 2
72.5794 N	38.5042 W	Summit, Greenland1	fn_dksummit
1NSIDC recommends users use the GC-Net Summit station data acquisitions instead of the IASOA Summit, Greenland data acquisitions since the data are the same. 2The Abisko, Sweden site data has not been delivered so this site is not available on the search yet.

Data Output

CSV Files

The MIST data output are supplied in a text Comma Separated Value (CSV) File format. CSV files are a common interchange format between software packages supporting tabular data, and are also easily manipulated with a text editor such as Note Pad, a spreadsheet application such as Microsoft Excel, or with end-user written scripts or programs. There are two types of CSV files that are generated for each data search: raw and processed.

Note: Each row of data in the CSV file is considered a chip. A chip is equal to a 49 square kilometer area on the Earth. MOD11A2 generates a 7 x 7 size chip at 1 km grid resolution, and MOD09A1, MOD10A1, MCD43A1, MCD43A2, and MCD43A4 generate a 14 x 14 size chip at 500 m grid resolution.

Raw Data CSV File

The raw data CSV file contains the raw chip data with either 49 columns (1 km) or 196 columns (500 m) of data depending on the chip resolution. No processing is done on these data.

Raw Data CSV File Format

The raw data are supplied in either a 7 x 7 (1 km) or a 14 x 14 (500 m) data grid. MOD11A2 generates a 7 x 7 data grid, and MOD09A1, MOD10A1, MCD43A1, MCD43A2, and MCD43A4 generate a 14 x 14 data grid. Tables 4 and 5 show the pixel numbering scheme for each size grid.

Table 4. Pixel Numbering Scheme for MODIS 1km Data Grid

1	2	3	4	5	6	7
8	9	10	11	12	13	14
15	16	17	18	19	20	21
22	23	24	25	26	27	28
29	30	31	32	33	34	35
36	37	38	39	40	41	42
43	44	45	46	47	48	49

Note: The red box is the site pixel.

Table 5. Pixel Numbering Scheme for MODIS 500 m Data Grid

1	2	3	4	5	6	7	8	9	10	11	12	13	14
15	16	17	18	19	20	21	22	23	24	25	26	27	28
29	30	31	32	33	34	35	36	37	38	39	40	41	42
43	44	45	46	47	48	49	50	51	52	53	54	55	56
57	58	59	60	61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80	81	82	83	84
85	86	87	88	89	90	91	92	93	94	95	96	97	98
99	100	101	102	103	104	105	106	107	108	109	110	111	112
113	114	115	116	117	118	119	120	121	122	123	124	125	126
127	128	129	130	131	132	133	134	135	136	137	138	139	140
141	142	143	144	145	146	147	148	149	150	151	152	153	154
155	156	157	158	159	160	161	162	163	164	165	166	167	168
169	170	171	172	173	174	175	176	177	178	179	180	181	182
183	184	185	186	187	188	189	190	191	192	193	194	195	196

Note: The site pixel is in one of the four red boxes.

Processed Data CSV File

The processed data CSV file contains aggregated data for each chip. For coded data, the number of valid pixels, value of the center pixel, and the statistical mode of the chip is calculated. For non-coded data, the mean, minimum, maximum, and standard deviation of the valid pixels in the chip are also calculated. The processed CSV file also translates the values for the non-coded rows, converting them from the raw data number to a geophysical parameter, such as albedo, temperature, angle, etc. The processed values are more readily usable, but are aggregated so there are fewer columns available. Thus, the raw file will typically have more columns than the processed file.

The processed coded data CSV file contains the following information:

• Product Name
• Site ID
• Band/Parameter Name
• Date of Temporal Coverage and/or Intra–annual Range (in day of year format)
• Num_Valid_Pixels
• Center_Pixel
• Mode

The processed non-coded data CSV file contains the following information:

• Product Name
• Site ID
• Band/Parameter Name
• Date of Temporal Coverage and/or Intra–annual Range (in day of year format)
• Num_Valid_Pixels
• Center_Pixel
• Mode
• Mean
• Min
• Max
• Standard_Dev

Saving Search Results, Data CSV Files, and Graphs

Cookies are used to retain user options and Session IDs. The search results, data CSV files, and graphs are saved in a Session ID cookie for 72 hours.

Thus, for 72 hours, the search results and the data CSV files can be retrieved in the Results Summary section of the interface, and the graphs can be retrieved in the Graph Results section of the interface. However, the Results Summary information is not the actual data, but displays the following information for each search result:

• Result ID Number
• number of rows in the CSV file
• the product(s)
• the parameter(s)
• Site ID Number(s) that were chosen for each search

In order to save the actual data CSV files to a local disk for later use, click on the Save This Search button located in the Subsetter Search section of the interface. And to save a graph, open up the PostScript version of the graph and save it to a local disk.

Types of Graphs

There are three different types of graphs that can be created:

• Folded - Time Series
• Normal - Time Series
• Scatterplot.

Click on the thumbnail to view the full resolution image (95 KB jpg).

Figure 1. A Folded - Time Series Graph of MOD09A1 Band 1 Surface Reflectance at Swiss Camp, Greenland for the period 10 May to 15 November, for the years 2000 - 2007. Points are mean with standard deviations for error bars.

Click on the thumbnail to view the full resolution image (102 KB jpg).

Figure 2. A Normal - Time Series Graph of MODIS Surface Reflectance from MOD43A4 Band 1, Summit, Greenland and Band 4, Swiss Camp, Greenland; and MOD09A1 Band 4, Swiss Camp.

Click on the thumbnail to view the full resolution image (53 KB jpg).

Figure 3. A Scatterplot Diagram of MODIS Band 4 Surface Reflectance at Swiss Camp, Greenland, from MOD09A1 (total) vs. MOD43A4 (nadir).

Share Your Thoughts

In order to aid us in future development of this tool, please share your feedback on the usability of this interface by taking the MIST Usability and Feature Request Survey.