LUQ LTER DATA SETS DOCUMENTATION FORM

ON-LINE VERSION

A DATA SET is a series of observations collected by the same methodology. Each data set should have documentation sufficient for someone unfamiliar with the research to replicate the study. Data sets may be broken into subsets (data files) that are discrete in space and time, in that order. The documentation for a data set should include all spatial and temporal subdivisions of the data.

(Data, Abstract, Methods, Variables)

NOTES:

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DATA SET IDENTIFIER: Urban-Rural Temperature Data

PROJECT TITLE: The relation between land-cover and the Urban Heat Island in San Juan, Puerto Rico

PROJECT DESCRIPTION: Population movements, growth and industrialization are causing rapid urbanization throughout the tropics, which can result in elevated temperatures within urban areas when compared to surrounding rural areas, a phenomenon known as the Urban Heat Island (UHI). One such example is the city of San Juan, Puerto Rico. Our objective in this study is to quantify the UHI created by the San Juan Metropolitan Area over space and time using temperature data collected by mobile and fixed-station measurements. We used the fixed-station measurements to examine the relation between average temperature at a given location and the density of vegetation located upwind. We then regressed temperatures against regional land-cover to predict future temperature with projected land-cover change. Our data show the existence of a nocturnal UHI, with average nighttime urban-rural temperature differences (ΔT_U-R) of up to 3.02°C.  Urban-rural temperature differences had negligible seasonal differences. Comparisons of diurnal temperature trends at urban, grassland, and forested sites indicate that canopy cover reduced daytime warming.  Results from the mobile measurements show that the UHI has reached the base of the Luquillo Mountains. Temperature was predicted best (r² = 0.94) by vegetation in upwind easterly directions, especially that within 180 meters of the sensor.  Predictions of future development and temperatures suggest that if the present pattern of development continues, over 140 km² of land that showed no signs of UHI in 2000 will have an average annual UHI between +0.4°C and +1.55°C by 2050. Furthermore, more than 130 km² of land area with a current UHI between +0.4°C and +1.4°C in 2000 will have an average UHI greater than +1.55°C by 2050.

LTER CORE AREAS: Annotate all that apply (See online list)

LEF LTER 1 RESEARCH TOPIC (Annotate all that apply) (See online list)

We define a data file as a component of a data set. A data set can have only one data file or more. Basically, different data files have different data structures or format.
DATA SET FILES (SUBSETS):

RESEARCH LOCATION:

INVESTIGATORS: David Murphy

SOURCE OF FUNDING (SPONSOR): NSF LTER Program

DATA SET ABSTRACT: each of the stations listed in this excel file were used to calculate the urban heat island created by the San Juan Metropolitan Area.

DATA SET METHODS: The overall goal of the fixed-station transects was to establish simultaneous temperature measurements to assess the timing of the peak diurnal and seasonal UHI and the influence of land-cover on temperature. The fixed-station measurements consisted of a network of ten automated Series-8 HOBO Pro-Temp Data Loggers (Onset Corporation, Pocasset, MA), calibrated to each other and to the ASOS temperature sensor at San Juan airport, to record temperature measurements near different types of land-cover ranging from the center of San Juan to barely developed regions 20 km to the east of the city center. We attached the HOBO sensors to telephone poles about 3 meters above the ground surface. The sensors were all placed within 50 meters of sea level, so elevation should not influence our results. Air temperature measurements were logged automatically at 5 minute intervals, and then aggregated into hourly averages for data analysis. We did not measure humidity because temperature was the primary focus of this study and because the atmospheric controls on humidity are varied and different than that for temperature.

The HOBO temperature loggers had internal sensors that, according to the manufacturer's specifications, have a 90% response time in still air of up to 35 minutes and an accuracy of ±0.2°C over the range of temperatures measured in Puerto Rico. The error would be larger if radiation errors were present, but we placed the loggers in naturally ventilated radiation shields provided by Onset specifically to reduce radiation-caused error. Temperature measurements collected during calibration exercises performed in a laboratory resulted in an average standard deviation among all sensors of 0.11°C.

REFERENCES :

CROSS-REFERENCES (other data sets related to this one):

SAMPLE LOCATION : N/A

STORAGE SITES (of data files): ON-line

INVESTIGATOR'S ASSIGNED KEYWORDS: UHI, San Juan Metropolitan Area

LEF LTER OFFICIAL KEYWORDS (See table):

PUBLICATIONS : Murphy, D. J. R., M. H. P. Hall, C. A. S. Hall, G. Heisler, S. Stehman, and Carlos Anselmi-Molina. 2009: The Relation Between Land-cover and the Urban Heat Island in Northeastern Puerto Rico. International Journal of Climatology, (submitted)

DISSEMINATION: unrestricted

RESTRICTED UNRESTRICTED

REASONS TO RESTRICT DATA IN THIS DATA SET BEYOND ITS TWO YEAR POLICY PERIOD*:

*WILL HAVE TO BE APPROVED BY LTER PRINCIPAL INVESTIGATORS: N. BROKAW, A. LUGO

FILING

___ "File" copy only : Data Management will only file an electronic copy of the data file and its documentation 
___ "Enter" data on-line : Data Management will be in charge of entering the data on computer files (Contact Eda C. Meléndez)

SITES DESCRIPTIONS:

HOBO ID	Land-Cover	Detailed Site Description
1S	Abandoned agricultural fields	Thickly vegetated fields with multiple types of long grass species. Few trees present. Sky view factor greater than 75%. No buildings. One single-lane asphalt road.
2S	Urban Center	Intersection of two single-lane old asphalt roads. Buildings on three of four corners, with a building road ratio of about 1:1, with one larger church steeple, at a building road ratio of 2:1. Sky view factor greater than 50%.
3S	Industrial	<500 meters downwind of a major pharmaceutical plant. A single one-story building near sensor. Mainly grass and bushy vegetation surrounding nearby building. Sky view factor greater than 75%. Building-road ratio around 1:1
4S	Residential	Hobo was placed on a one-lane road bisecting two neighborhoods, one directly east and one directly west. Building-road ratio of about 1:1, and a sky view factor >50%.
5S	Major road crossing	Intersection of two four-lane roads. Car traffic extremely high during rush hours. Two-story mall located 300 meters southeast, and an industrial complex located 400 meters northeast. Sky view factor greater than 50%. Buildings too far for a building road ratio.
6S	Mowed-grassland	Mowed grassland located approx. 200 meters south of a major shopping center, and about 50 meters south of the parking lot for the shopping center. Vegetated hills to the east and south, about 30 meters in height, and covered approximately 30% by trees. Sky view factor of 82.5% (Figure 2).
1A	San Juan Central Business District (CBD)	Located at the intersection of one large road and one side street. Small trees line the south side of the side street, and also the west side of the large road, but do not limit sky view much. Two large buildings to the southeast and southwest have building road ratios of about 8:1, while the building to the northeast has a ratio of 3:1. Sky view factor of about 68.8% (Figure 2).
2A	Old-growth forest	HOBO placed on tree trunk 10 - 20 meters below a full canopy and about 30 meters from the edge of the forest. Broadleaf, climax tree species dominate. Sky view factor is 6.5% (Figure 2).
3A	Grassland mix	This site is located 15 meters south of the old growth forest. There is a field of short grass species to the east, and an industrial complex directly to the west. Sky view factor greater than 50%, with a building road ratio of 1:1.
4A	Residential Limits	HOBO placed at the northern end of a residential neighborhood. The area due east and northeast is wild grassland with sparse tree coverage for +5 Km upwind. Housing structures about 100 meters south. Placed near one short tree (about 4 meters high). Sky view factor greater than 75%

location	latitude	longitude
1S	18°22.349'	66° 02.626'
2S	18°22.204'	65° 59.314'
3S	18°22.034'	65° 57.635'
4S	18°21.739'	65° 53.530'
5S	18°21.866'	66° 01.128'
6S	18°22.138'	65° 55.806'
1A	18°22.744'	65° 50.982'
2A	18°25.751'	66° 02.888'
3A	18°23.156'	66° 05.543'
4A	18° 25.184'	66° 14.701'

VARIABLES (ATTRIBUTES):

COMPUTATIONAL METHODS:

  FOR DATA MANAGER USE ONLY

DATE OF LAST REVIEW: December 7, 2009

DATE OF LAST ENTRY: July 5^th, 2006

STAGE OF DATA SET MANAGEMENT (dates):

RECEIVED: May 15, 2009
ENTERED: May 15, 2009
FILED ON-LINE: Dec 1, 2009
REVIEWED BY RESEARCHER:

FILING MEDIA :

NAME OF DOCUMENTATION FILE :  LEF - LTER metadata form- DJM.doc, lterdb167.htm
NAME OF ON - LINE CATALOG :  LTERDBAS
RECORD # : 167
DOCUMENT TYPE :  digital only
PRIORITY TO BE ENTERED : N/A

Rev.date of this form: 28 July 200/ 15 July  2001/June 9, 2003/March 16, 2004/12 April 2005/ 8 November 2005