NEXRAD HDSS Access Tutorial
This tutorial guides the user through the Nexrad portion of the HDSS Access System (HAS).
Background:
The HDSS is the robotic tape assembly used to store large datasets at NCDC.
The data must be transferred from the tapes onto the public ftp site. The HAS web interface allows
users to order Nexrad data from the tape archive. An average sized order takes 5-25 minutes to post
on the ftp site.
- Go to the HAS website: http://has.ncdc.noaa.gov and
select the type of data desired.
Level-II is the raw data, Level-III is a collection of derived products.

- Now choose the type of retrieval. Using the Stations(s) option usually provides an easier
search for specific data.

- If Entire Dataset is selected, then choose date range.

- If Station(s) is selected, then choose station (hold shift or control for multiple) and date range.

- After entering your email, choose the desired files. The 4-letter Nexrad Site ID and date are included
in the filename.
NOTE: The "UnTar Files After Retrieval" option allows for the
files to be uncompressed for the user. This option is useful when only select dates or products
are needed. Individual Level-II files will still have unix compression
after retrieval.

- If you have chosen to "UnTar Files After Retrieval" select the desired individual files. Multiple
files may be selected by holding shift or control during selection. The filename format
is as follows:
Level-II Example) KAKQ
20030919_
210227
.Z -
495042
KAKQ = Source Radar Site ID
20030919 = Date in YYYYMMDD format (year=2003, month=09, day=19)
210227 = Time in HHMM format Z/UTC time (hour=21, minutes=02)
.Z = Unix compression extension
495042 = Size of file in Bytes
Level-III Example) KAKQ
SDUS51_
N0R
AKQ_
20030919
2102 -
11730
KAKQ = Site ID of transmitting radar (not necessarily source radar)
SDUS51 = Transmission info
N0R = Product Code (Product List)
AKQ = Source Radar Site ID (ACTUAL SITE OF THE DATA!)
20030919 = Date in YYYYMMDD format (year=2003, month=09, day=19)
2102 = Time in HHMM format Z/UTC time (hour=21, minutes=02)
11730 = Size of file in Bytes

- You have now submitted an order to the HDSS System. An email will be sent to you when the order has
been completely posted to the ftp site.

- The email with the HAS Job Number and instructions on data access.
