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T he NOAA-CREST weather station is located on the roof of the Marshak Science Building.  It has been gathering data continuously since it began operation on 12 December, 2003. The station's sensor array collects data in one-minute cycles controlled by the program resident in a datalogger at the site.  The datalogger is polled and information downloaded to the host computer in the Grove School of Engineering via the campus internet.

Archived data is available for research purposes in tabular format both with and without headings, and the same data is published to this NOAA-CREST web site. Data includes wind speed, direction and their vectors; air, dew point, wet bulb, heat index and wind chill temperatures; relative humidity; air pressure; rain; plant trans-evaporation and solar flux. Other instrumentation is located on the roof of the Steinman Engineering Building and the NAC Building (North Academic Center including the Student Center) on the CCNY campus. Several remote sensor sites are additionally located at associated academic campuses. You may click on above image to view the CCNY weather station installation.

The reference global position of the weather station instrument array is Longitude North 40.81920857°, Latitude West 73.94904472° and 98.365 m (322.637 ft) above mean sea level. (Correction from prior.)

You may contact the Weather Center Staff about questions, broken links or specific data products. Please send an email to Weatherman.

Real-Time Weather Data is updated every minute. A table of data selected from the larger Weather Report.

A Discussion of the utility of these data in real-time wind current data mapping by Brookhaven National Laboratories can be viewed here.

• Real-Time Weather Data

Graphical presentations showing the current weather histories derived from CCNY site instrumentation.

• CCNY Displayed Current Weather - 36 hour integrated graph - This graph is updated every 15 minutes. (Air Temperature and Pressure, Relative Humidity, Solar Flux)

• NOAA/GSD 24 hour graphs - Ground-Based GPS Meteorology (GPS-MET) Current Conditions for past 24 hours. (Air Temperature, Pressure and Relative Humidity)

• NOAA/GSD 3 day graphs - Ground-Based GPS Meteorology (GPS-MET) Current Conditions for past 3 days

• NOAA/GSD 5 day graphs - Ground-Based GPS Meteorology (GPS-MET) Current Conditions for past 5 days.

• Quick-look NOAA/GSD graphs - Ground-Based GPS Meteorology (GPS-MET) Current Conditions for past 5 days (Air Temperature, Pressure, Dew Point, IPW [inches of precipitable water in the atmospheric column] and Relative Humidity)

A graphical representation of major weather data trends updated every night for Air Temperature and Pressure, Relative Humidity, Solar Flux. 

• Daily Weather Trends Archive

Comprehensive data sets listed by YYMMDD format. The time stamp is in Eastern Standard Time (EST); Daylight Savings Time does not apply.

• Daily Weather Report Archive

• Monthly Weather Report Archive (compressed format)

Lidar is an acronym standing for LIght Detection And Ranging, a technique using a laser beam source while measuring the time and intensity of reflected energy. We use it to measure aerosol vertical concentration versus time in the Earth's atmosphere.

• Lidar Page (Discussion, Data, References and Bibliography)

• Archive of Lidar images by day and view all wavelengths

• Archive of Lidar images by date range selection (1064nm only)

• Archive of raw Lidar data (compressed format)

• Recent Lidar Images:

  Click on these links to view samples of recent CCNY Backscatter Lidar images taken at the wavelengths of 355 nm,
  
  532 nm,
  
  and 1064 nm.
  
  From these data and correlation with others, the Aerosol Optical Depth (AOD) is determined, viewed here.
  
  (Click again or click image to hide. You may right-click and select 'view image' to display full size in a new window and then use your back button to return to this page.)

LIDAR elastic backscatter reflection from clouds, aerosols or precipitation is used to measure cloud base height and vertical visibility, and is particularly suited for low altitude measurements. This instrument can measure up to three layers of clouds simultaneously using a high powered pulsed laser diode in the infrared region at 910 nm. Pulse repetition can be varied from 2 to 120 seconds and fast repition rates can be used to detect thin cloud patches below a solid cloud base.

Ceilometer backscatter profile data can be used to derive the distribution of the time averaged cloud fraction over the site and the distribution of boundary layer aerosols. This data can also be used to derive the atmospheric extinction ratio at low altitudes (near-ground to 25,000 ft [7.5 km].)

Continuous high resolution water vapour mass mixing ratio profile measurements are of interest and provide detail not possible with radiosondes. The ceilometer can show the variation in the height of the boundary layer, above which the water vapour mass mixing ratio can rapidly fall to a low level. This ability to make water vapour measurements by day is important in the study of the variability of water vapour profiles and convective activity in the boundary layer.

Originally, our measurements were taken in the standard measuring mode, where the CL31 digitally samples the return signal every 67ms from 0 to 50 microseconds, providing a spacial resolution of 10m with data-averaged messages received every 2 seconds. A B&B Electronics model ESR901 RS-232 Serial to Ethernet converter is installed in the Ceilometer base on the roof, connecting to the campus internet and mapped to a virtual COM port on the remote data collection computer. The data is recorded using Hilgraeve's HyperTerminal Private Edition, parsed and converted to image files using either a Matlab or IDL routine. Each data message represents 770 value points for the vertical column.

Starting 13 October, 2006, the CL-31 data format was changed to 10m x 770 samples, 15 seconds data collection interval with data averaging, and with error H2 on, setting the range gate normalization so that all data, including noise is normalized.

The CL-31 electronics were upgraded on 13 February, 2007 with a new engine supplied by Vaisala. There were no other changes in operation and no noticeable changes in data quality.

• Archive of Ceilometer images

• Technical Data.

• Instruction Manual (for student, staff and faculty use at CCNY only)

• References:

  • Beaubien, Mark and Freedman, Jeff, "Comparison of Two Imager-based Methods for Determination of Winds Aloft", Yankee Environmental Systems, Inc. and Atmospheric Sciences Research Center, SUNY/Albany. Albany, NY (2001)

The MFR-7 Shadowband Radiometer measures total, diffuse, and direct irradiance at six wavelengths (415, 500, 615, 673, 870, and 940 nm, each 10 nm FWHM) in the visible/NIR spectrum. The instrument makes measurements simultaneously across the seven channels and is displayed in near-real time updated every 15 minutes. Data are used for atmospheric turbidity measurements. These data may be viewed as Calibrated and Langley plots by accessing the CCNY-YESDAS Web webserver from the link below. Data sets may be downloaded for further use. Historical data files may also be accessed. The time stamp is Eastern Standard Time (EST); Daylight Savings Time does not apply.

Instruments are deployed at remote sites with a marine battery backup, each operating autonomously unattended and requiring little attention or service. Each unit is connected to the internet through a MOXA DE-311 Serial to Ethernet converter installed in each control box located on the site roof and mapped to a data collection computer. Data is downloaded at fifteen minute intervals, converted and incrementally transmitted to a central data server by controlling script files using an automated FTP client from ScriptFTP and also Visual Basic programs which generate command files executed by the computer's System Scheduler.

Overall system design is fault tolerant. Data, in different forms, is stored in three places such that data integrity is not compromised by communication losses or internet interruptions. Files are automatically corrected and restored upon power loss or internet failure, the exception being failures due to the instrument itself, for example, a lightning strike.

• Current Shadowband Data and Archive.

• Raw Shadowband Data Archive.

• Movie of the MFR-7 Shadowband Radiometer in operation.

• Supporting Instrument Documentation (for student, staff and faculty use at CUNY only)

  • YESDAS Manager (Software) Installation Manual and User's Guide v2.1

  • YESDAS Manager (Software) Installation Manual and User's Guide v2.2

  • MFR-7 (Hardware) Installation Manual and User's Guide v2.1

  • MFR-7 (Hardware) Installation Manual and User's Guide v2.2

  • PCMCIA Memory Card Option v1.0

• Further information about the MFR-7 instrument.

• Reference:

  • Harrison, Lee and Michalsky, Joseph, "Objective Algorithms for the Retrieval of Optical Depths from Ground-Based Measurements", Appl. Opt., 33, 5126-5132 (1994).

The Trimble 5700 receiver and Trimble Zephyr GPS antenna located within the weather station instrument array continuously monitors the signal time delay from several geosyncronous satellites. These delay times are transmittted to NOAA and processed together with selected weather data from our site to derive a set of raw delay times. This data set is then further interpreted in context of a larger time-managed spacial array of other sites' data to derive the moisture content in the air column over our site every 30 minutes. Time stamp is in UTC (GMT).

Accurate station pressure and corresponding elevation measurements are critical in terms of estimating water vapor. GPSMet's precision target is 0.5mm of water vapor, striving to obtain pressure and elevation measurements accurate and precise to within 0.1 hPa and 1 m whenever possible. For example, the elevations of the station listed below are (in m): SA22 = 28; SG06 = 54; CCNY = 98, -> SG06 - SA22 = 26m and -> CCNY - SA22 = 70m. Therefore, we would expect SG06 to be about 2.6 hPa lower than SA22: 1020.2 - 1016.3 = 3.9 (data from a typical day) and CCNY to be about 7 hPa lower than SA22: 1020.2 - 1011.4 = 8.8. This assumes a 'calm' (near 0 wind speed) day. In these cases the pressure gradient across large (10's of km) distances will be near 0. On the other hand, in case of active weather such as a frontal passage there will of course be pressure gradient. However, given the relatively close spacing of the sites you would expect to see a very good correlation between the time series accross the relatively close sites below.

Site location maps are referenced below for your convenience.

• PWV Local Site Data (these may be large files, size dependent on the day of the year, up to 2.5Mb.) Click on link to view in your browser window, or right-click and select 'Save Link As' to download the file.

  • CCNY (The City College of New York, Manhattan, NY)

  • MOR1 (East Moriches, Long Island, NY)

  • SG06 (Stony Brook, Long Island, NY)

  • SA22 (Union, NJ)

  • The Data Table Heading for the PWV datafile.

• Current IPW and MET Observations from NOAA/GSD Ground-Based GPS Metrology (GPS-MET)

• NOAA/GSD Ground-Based GPS Metrology (GPS-MET) Real-Time Water Vapor Interface A date-range selection and multi-site comparison tool for IPW and MET observation data from ground-based, radiosonde and other sources.

• Discussion of Atmospheric Water Vapor and NOAA/FSL Ground-Based GPS Metrology (GPS-MET)

References:

• Daniel Birkenheuer, Seth Gutman, "A Comparison of GOES Moisture-Derived Product and GPS-IPW Data during IHOP-2002", J. of Atm. & Oceanic Tech, 22, 1838-1845, 2005.

• Tracy Lorraine Smith, S. G. Benjamin, S. I. Guthman and S. Sahm "Short-Range Forecast Impact from Assimilation of GPS-IPW Observations into the Rapid Update Cycle", Monthly Weather Review, Nov, 2006.

The TSI-440 is a full color 24 bit digital imaging and software system designed to automatically monitor cloud conditions.  It was developed jointly in the late 1990's by Charles Long, (then with SRRB, see reference below), the spherical dome control system designed by the Geophysical Instruments and Measurements group at Brookhaven National Laboratory, Penn State University, Yankee Environmental  Systems, Inc. and manufactured by YES Inc. The instrument uses a commercial ethernet ready, IP addressable neutral density filtered CCD camera looking down on a sky-facing, highly polished and waxed stainless steel convex hemispherical mirror to take pictures of the sky at one minute programmed intervals during daylight hours when the sun is 10 degrees or more above the horizon. The 352 x 288 pixel images are captured, stored and processed by a remote computer.

A modifiable filtering algorithm applied to the images distinguishes clouds and thin clouds from clear sky based on the red/blue intensity ratio of each camera pixel.  Image sets may be reevaluated by applying new algorithm parameters to post processing.  The current applied filter settings are: clear/thin: 14, thin/opaque: 27, sunny: 50.  The sun's reflection as it travels across the sky is blanked out by a black band on the mirror surface and positioned under software control based on latitude, longitude, date and time of day.  The camera mounting arm and the black band are removed from the image before computation of cloud coverage by the use of a computer generated mask.

Systematic errors in the evaluation of the pixel array can be introduced by specular reflection from the black sun blocking mirror band on bright cloudless days, accumulated dust, deposited dirt from rainwater and random bird droppings on the mirror surface, therefore routine maintenance is expected. Specular reflection is a particularly annoying source of error, typically interpreted as about 4% cloudcover for an otherwise bright and cloudless day.

Sky images are stored in JPG format and cloud screened or interpreted processed images are stored in PNG format. In addition, each JPG image can be processed to include the date, time and atmospheric conditions.  Data is analyzed to provide daily fractional cloud cover in ASCII text format associated with each daily set of sky images. The time stamp is UTC Time, or -5:00hrs EST, -4:00hrs EDST.

• The image-cloud cover pair of the last processed sky image

• Sky Image Movies can be selected from this list. The camera arm support is pointed true North from the center of the vield of view. Some browsers may require a click on the image to play. If the image does not load, you do not have a current image viewer plugin installed. Please update your media viewer. Firefox or Opera browsers are recommended.

• Information on the TSI-440 instrument

• References:

  • J. Mauer, "Cloud Detection Over Snow and Ice Surfaces: Summet Camp Greenland", University of Colorado, Boulder, 2003.  (Comparison of MODIS with TSI and other ground based measurements.)

  • J. M. Saaburg and C. N. Long, "Improved Sky Imaging for Studies of Enhanced UV Irradiance", Atmos Chem Phys 4, pp 2543-2552, 2004.

  • S. Ackerman, K. Strabala, P. Menzel, R. Frey, C. Moeller, L. Gumley, B. Baum, C. Schaaf and C. N. Long, "Discriminating Clear-Sky from Cloud with MODIS Algorithm Theoretical Basis Document (MOD35)", Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin - Madison, 1997.

  • S. Ackerman, K. Strabala, P. Menzel, R. Frey, C. Moeller and L. Gumley, "Discriminating Clear Sky from Clouds with MODIS", J. of Geophys. Res., vol 103, No. D24, pp 32,141-32,157, 1998.

  • P. Menzel, S. Seeman, J. Li and L. Gumley, "MODIS Atmospheric Profile Retreivel Algorithm Theoretical Basis Document", Cooperative University of Wisconsin - Madison, 2002.

  • D. Diner, L. Girolamo, and E. Clothiaux, "Multi-angle Imaging Spectro-radiometer Level 1 Cloud Detection Algorithm Theoretical Basis", Jet Propulsion Laboratory, California Institute of Technology, 1999.

Our Aeronomy Lab, constructed in the Winter 2006 - Spring of 2007, sits atop the Administration Building on the CCNY campus to gather air quality data. The 140 sq ft structure is fully insulated to provide a temperature controlled environment for sensitive instrumentation and provides workspace for additional specific-goal research projects.

• PM 2.5 (particulates) and O₃ (Ozone concentration) Data can be retrieved here. The New York State Department of Environmental Conservation operates equipment in our lab to gather and report this concentration data representing particulates 2.5 micrometers (2.5μ) in size or smaller aerodynamic diameter. Since airborne particles have irregular shapes, their aerodynamic behaviour is expressed as the diameter of an idealised spherical particle known as aerodynamic diameter.

  Reports, graphs and downloads in various formats can be produced along with comparisons of data from nearby Metropolitan New York sites. Select the 1024x768 screen size to view properly in your browser when extracting comparison graphs.

• A description of the TEOM PM2.5 instrument and principles of operation can be found here.

Our sun photometer instrument is #237 in the NASA AERONET (AErosol RObotic NETwork.) This microprocessor controlled, stepper motor positioned robot has a two component optical head containing the sun collimator without lens and the sky collimator with lenses and filter wheel. Sun tracking is controlled with a 4-quadrant detector. Data is temporarily stored in memory and once every hour uploaded to NASA via a GOES-E (geosyncronous) satellite uplink.

The instrument directly measures the incoming solar energy (sky radiance) at selected wavelengths of 340, 380, 440, 670, 870, 1020 nm (aerosols), and 936 nm (water vapor). Light is absorbed and scattered by atmospheric gasses, water vapor and aerosols. The concentration of different atmospheric components can be determined by the attenuation at wavelengths which are strongly absorbed or scattered. Total Optical Depth (TOD) is the sum of the Rayleigh Optical Depth (from atmospheric gasses, e.g. Nitrogen, Oxygen, Argon), the Ozone Optical Depth, the Mixed Gas Optical Depth (e.g. Carbon dioxide, oxides of Nitrogen), the Water Vapor Optical Depth and the Aerosol Optical Depth (AOD). AOD is of the most interest because it cannot be directly measured by other methods, and is determined by subtraction of the other quantities. Aerosol phase functions and size distribution can also be inferred. The sun photometer measurements are also important as standards for satellite-derived values of AOD. 

• Aerosol Optical Thickness (AOT) Data extracted from the NASA Version 1 database and uploaded daily. On July 1, 2005, the Version 2 Direct Sun algorithm (V2S) data were released. A summary of these changes can be read here.

• CIMEL CE318 sun photometer instrument information

• Link to NASA Aeronet

• Discussion of recent data processing algorithm changes