We thank Emily Meineke for contributions to the original study design and experiment. We thank Ryan Boyles for facilitating access to the study sites and weather-station data. Jaime Collazo, Steven Frank, and Erica Henry provided the data loggers and radiation shields. Access to study site was approved by the North Carolina State Climate Office. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

1. Construction of the Radiation Shield
<ol>
	<li>Using a utility knife, cut the corrugated plastic sheets into squares (Figure 1A). One 15 cm square and two 10 cm squares will be needed for each shield.</li>
	<li>Cuts for the top layer of the small radiation shield (Figure 1B; left image):
	<ol>
		<li>On the 15 cm square, measure 4 cm from one edge and draw a line with a pencil. Use a straightedge as a guide to score along the line. (Herein, &#8220;scoring&#8...

<ol>
	<li>Bowker, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anurans,+the+group+of+terrestrial+vertebrates+most+vulnerable+to+climate+change:+A+case+study+with+acoustic+monitoring+in+the+Iberian+peninsula.">Anurans, the group of terrestrial vertebrates most vulnerable to climate change: A case study with acoustic monitoring in the Iberian peninsula.</a> Computational bioacoustics for assessing biodiversity. , 43 (2007).</li><li>Walther, G. -. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ecological+responses+to+recent+climate+change.">Ecological responses to recent climate change.</a> Nature. 416 (6879), 389-395 (2002).</li><li>Inouye, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+climate+change+on+phenology,+frost+damage,+and+floral+abundance+of+montane+wildflowers.">Effects of climate change on phenology, frost damage, and floral abundance of montane wildflowers.</a> Ecology. 89 (2), 353-362 (2008).</li><li>Lundquist, J. D., Huggett, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evergreen+trees+as+inexpensive+radiation+shields+for+temperature+sensors.">Evergreen trees as inexpensive radiation shields for temperature sensors.</a> Water Resources Research. 44 (4), W00D04 (2008).</li><li>De Jong, S. A. P., Slingerland, J. D., Van De Giesen, N. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fiber+optic+distributed+temperature+sensing+for+the+determination+of+air+temperature.">Fiber optic distributed temperature sensing for the determination of air temperature.</a> Atmospheric Measurement Techniques. 8 (1), 335-339 (2015).</li><li>Holden, Z. A., Klene, A. E., Keefe, R. F., Moisen, G. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+evaluation+of+an+inexpensive+radiation+shield+for+monitoring+surface+air+temperatures.">Design and evaluation of an inexpensive radiation shield for monitoring surface air temperatures.</a> Agricultural and Forest Meteorology. 180, 281-286 (2013).</li><li>Terando, A. J., Youngsteadt, E., Meineke, E. K., Prado, S. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ad+hoc+instrumentation+methods+in+ecological+studies+produce+highly+biased+temperature+measurements.">Ad hoc instrumentation methods in ecological studies produce highly biased temperature measurements.</a> Ecology and Evolution. 7 (23), 9890-9904 (2017).</li><li>Richardson, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimizing+errors+associated+with+multiplate+radiation+shields.">Minimizing errors associated with multiplate radiation shields.</a> Journal of Atmospheric and Oceanic Technology. 16 (11), 1862-1872 (1999).</li><li>Anderson, S. P., Baumgartner, M. F., Anderson, S. P., Baumgartner, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radiative+Heating+Errors+in+Naturally+Ventilated+Air+Temperature+Measurements+Made+from+Buoys.">Radiative Heating Errors in Naturally Ventilated Air Temperature Measurements Made from Buoys.</a> Journal of Atmospheric and Oceanic Technology. 15 (1), 157-173 (1998).</li><li>Nakamura, R., Mahrt, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Air+temperature+measurement+errors+in+naturally+ventilated+radiation+shields.">Air temperature measurement errors in naturally ventilated radiation shields.</a> Journal of Atmospheric and Oceanic Technology. 22 (7), 1046-1058 (2005).</li><li>Tarara, J. M., Hoheisel, G. -. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-cost+shielding+to+minimize+radiation+errors+of+temperature+sensors+in+the+field.">Low-cost shielding to minimize radiation errors of temperature sensors in the field.</a> HortScience. 42 (6), 1372-1379 (2007).</li><li>Huwald, H., Higgins, C. W., Boldi, M. -. O., Bou-Zeid, E., Lehning, M., Parlange, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Albedo+effect+on+radiative+errors+in+air+temperature+measurements.">Albedo effect on radiative errors in air temperature measurements.</a> Water Resources Research. 45 (8), (2009).</li><li>Fuchs, M., Tanner, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radiation+shields+for+air+temperature+thermometers.">Radiation shields for air temperature thermometers.</a> Journal of Applied Meteorology. 4 (4), 544-547 (1965).</li></ol>

The accuracy and repeatability of air temperature measurements depend on the use of an appropriate solar shield that protects the sensor from direct and reflected solar radiation. Here we describe the construction of such a shield that is more compact in size, less expensive, or faster to construct than similar, previously described devices6, without sacrificing accuracy. 94% of the recorded temperatures for the thermochrons outfitted with the smaller shield were within 1.0 &#176;C of the best per...

In light of anthropogenic global warming, there has been a growing interest in recording air temperature in a variety of settings to understand and predict ecological responses to climate change1,2,3. With the advent of small, low-cost environmental data recorders (also referred to as data loggers, thermochrons, or hygrochrons), it is now possible to deploy high-density networks of sensors to measure hyper localized temperature variation, increasing ecologists&#39; ability to more directly observe the ambient environmental conditions experienced by organisms and ecosystems under study. Compared to existing, well-calibrated and rigorously tested&#8212;but sparsely distributed&#8212;permanent weather stations, such networks present opportunities to assess climatic variation on ecologically relevant scales but may reduce accuracy or comparability among studies if inconsistently or inappropriately deployed.
Near-surface air temperature sensors typically require some type of solar radiation shielding to prevent direct heating of the sensor element, which would result in erroneously warm measurements. Common ways to limit sensor bias include: 1) using existing environmental features such as trees for shading4, 2) bias correction and sensor calibration5 that derived corrections based on the thermal properties of sensors, and 3) the use of manufactured or custom fabricated shields6,7. Many researchers choose to use custom fabricated shields because of the low-cost and easy deployment, and necessity in situations where environmental conditions do not provide natural shading. However, a review of the ecological literature indicated that the design of custom fabricated shields varies widely among studies, and individual designs are rarely tested for accuracy. Untested shields can be susceptible to poor choice of materials and design that cause additional heating of the air molecules immediately surrounding the sensor, direct absorption of solar radiation by the sensor itself, or both-leading to average biases of up to 3 &#176;C7. On the other hand, simple and cost-effective designs6,7 are quite effective at shielding sensors (biases of 1 &#176;C or less) and are comparable to commercially manufactured radiation shields.
Here, we provide a detailed methodology for constructing a previously evaluated custom fabricated radiation shield7 for use with inexpensive thermochron temperature sensors. The shield design is a modification of one previously described and tested in an open Ponderosa Pine forest setting6. In recent tests of several custom-fabricated shield designs, this montane-tested shield resulted in the lowest biases when paired with small thermochrons7, but we found it cumbersome and too conspicuous to deploy in the field. The design protocol proposed here reduces the dimensions of the radiation shield by 50%. Such a reduction in size has several benefits: 1) it is less conspicuous and therefore less susceptible to tampering, 2) it can be more feasibly used in a wider variety of ecological settings where space is limited (e.g., on smaller urban street trees), 3) it is more accurate than other published shielding methods that attempt to minimize shield size or construction costs7, and 4) it is less expensive than the original, larger design due to the reduced quantity of construction materials required. After describing the construction methods, we explore the effect of the size reduction on sensor accuracy relative to the original shield design using results from a field trial conducted under high downward solar radiation conditions.

<table>
	<tbody>
		<tr>
			<td>Multipurpose Aluminum Foil Tape</td>
			<td>Nashua</td>
			<td>1087671</td>
			<td>48 mm width</td>
		</tr>
		<tr>
			<td>8&#34; cable ties</td>
			<td>DTOL</td>
			<td>GEN86371</td>
			<td>NA</td>
		</tr>
		<tr>
			<td>Corrugated plastic sheet&#160;</td>
			<td>Highway Traffic supply</td>
			<td>hts18X24COROW</td>
			<td>White sheet 18&#34;L x 24&#34;W, 5-pack</td>
		</tr>
		<tr>
			<td>Standard utility knife</td>
			<td>NA</td>
			<td>NA</td>
			<td>NA</td>
		</tr>
		<tr>
			<td>Standard Scissors</td>
			<td>NA</td>
			<td>NA</td>
			<td>NA</td>
		</tr>
		<tr>
			<td>Heavy duty stapler</td>
			<td>Swingline</td>
			<td>552277715</td>
			<td>NA</td>
		</tr>
	</tbody>
</table>

construction of a compact low-cost radiation shield for air-temperature sensors in ecological field studies

Low cost temperature sensors are increasingly used by ecologists to assess climatic variation and change on ecologically relevant scales. Although cost-effective, if not deployed with proper solar radiation shielding, the observations recorded from these sensors will be biased and inaccurate. Manufactured radiation shields are effective at minimizing this bias, but are expensive compared to the cost of these sensors. Here, we provide a detailed methodology for constructing a compact version of a previously described custom fabricated radiation shield, which is more accurate than other published shielding methods that attempt to minimize shield size or construction costs. The method requires very little material: corrugated plastic sheets, aluminum foil duct tape, and cable ties. One 15 cm and two 10 cm squares of corrugated plastic are used for each shield. After cutting, scoring, taping and stapling of the sheets, the 10 cm squares form the bottom two layers of the solar radiation shield, while the 15 cm square forms the top layer. The three sheets are held together with cable ties. This compact solar radiation shield can be suspended, or placed against any flat surface. Care must be taken to ensure that the shield is completely parallel to the ground to prevent direct solar radiation from reaching the sensor, possibly causing increased warm biases in sun-exposed sites in the morning and afternoon relative to the original, larger design. Even so, differences in recorded temperatures between the smaller, compact shield design and the original design were small (mean daytime bias = 0.06 &#176;C). Construction costs are less than half of the original shield design, and the new design results in a less conspicuous instrument that may be advantageous in many field ecology settings.

Representative results using thermochrons outfitted with the new, smaller shield design, the original larger shield design, and the thermochrons with no radiation shield are shown in Figure 2 and Figure 3. These data were recorded at a fully exposed rural location near Raleigh, NC (35.728&#176;N, 78.680&#176;W), and were affixed to a well-calibrated permanent weather station outfitted with a VAISALA platinum resi...

Watch this Scientific Journal Video about Construction of a Compact Low-Cost Radiation Shield for Air-Temperature Sensors in Ecological Field Studies at JoVE.com

Construction of a Compact Low-Cost Radiation Shield for Air-Temperature Sensors in Ecological Field Studies

With the advent of small, low-cost environmental sensors, it is now possible to deploy high-density networks of sensors to measure hyper localized temperature variation. Here, we provide a detailed methodology for constructing a compact version of a previously described custom-fabricated radiation shield for use with inexpensive thermochrons.

Low cost temperature sensors are increasingly used by ecologists to assess climatic variation and change on ecologically relevant scales. Although ...

This method for constructing a low-cost radiation shield can help improve air temperature measurements in ecological field studies. The main advantage of this technique is the small size of the shield which reduces construction cost to less than half that of similar models and makes your instruments less conspicuous in the field. To construct a radiation shield use a utility knife to cut corrugated plastic sheets into one 15 centimeter and two 10 centimeter squares.For the top layer of the small radiation shield, use a pencil to draw a line four centimeters from one edge of the 15 centimeter square and use a straight edge as a guide to score along the line. Next, measure 3.8 centimeters from the edges perpendicular to the four centimeter line, and use the straight edge to score from the bottom of the square up to the four centimeter line. Then draw a line from both corners above the four centimeter line to the junction of the four centimeter and 3.8 centimeter lines, and cut along this line.For the middle and bottom layers of the small radiation shield, use the straight edge to draw a six centimeter square in the middle of each 10 centimeter square, and score all around each six centimeter square, and from each corner of the six centimeter squares to the outer corners of the 10 centimeter squares. Now, fold the 15 centimeter sheet along the scored lines, and tuck the small triangular flaps on the inside of the larger back flap, securing temporarily with binder clips, and completely cover the scored side with aluminum foil tape. When the 15 centimeter square is folded correctly, the cut edge of the back flap will be flush with the folded sides, and the entire convex surface will be taped.Then use aluminum foil tape to completely cover the scored side of one of the 10 centimeter squares, and the unscored side of the other 10 centimeter square. Using a 1/4 inch drill bit, drill holes in each of the shields'layers, and run a cable tie through the eyelet of the censor housing and through the holes of the underside of the 10 centimeter square that is taped on the scored side and has the two holes drilled into the middle. Pinch the sides of each 10 centimeter square along its diagonal scored lines, using a heavy duty stapler to hold the pinched sides together.The end product will have a square bowl shape. When the second bowl is finished, thread a cable tie first through the left back hole of the 10 centimeter sheet taped on the unscored side. Then, through the left back hole of the second 10 centimeter sheet, leaving a two centimeter vertical space between the two sheets to allow airflow around the temperature censor.Thread a cable through the back right holes in the same way, and pass a cable tie through the two side by side holes in the back left of the 15 centimeter square sheet. Attach this tie to the 10 centimeter sheets, leaving two centimeter of space between the 15 centimeter sheet and the top of the upper 10 centimeter sheet, and thread the two side by side holes in the back right of the 15 centimeter sheet in the same manner. For mounting, drill additional holes into the back end of the assembled product as necessary.Then pass one cable tie through all three holes in the front of the sheets, and tighten the cable tie, taking care that the space is even between all three sheets. Ensure that the three sheets lay parallel to the ground when mounted. In this representative field experiment, positive biases were found across all four tested censors using the small radiation shield that were similar to those obtained using the original larger shield design, but were much less than the biases of the unshielded censors.The small shields also resulted in the recording of some outlier warm temperatures relative to the original shield design, although the overall differences were small. Warm biases were strongest during periods of peak solar radiation, but in both the small and large shield cases, these biases were much less than the biases of the unshielded censors. The mean temperature differences between all of the combinations of censors outfitted with the small radiation shield compared to the original design, revealed that the largest differences occurred at 08:00 hours local time.When constructing this shield, it's important to remember to completely cover each square with the reflective aluminum tape, to keep even spacing between the squares, and to mount the final constructed shield parallel to the ground. Measuring microclimatic variation in air temperature can help provide insights into local biological responses to recent and projected climate change. Using a radiation shield with well documented properties can help ensure meaningful comparisons between studies.

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7.9K Views.  Southeast Climate Adaptation Science Center. This method for constructing a low-cost radiation shield can help improve air temperature measurements in ecological field studies. The main advantage of this technique is the small size of the shield which reduces construction cost to less than half that of similar models and makes your instruments less conspicuous in the field. To construct a radiation shield use a utility knife to cut corrugated plastic sheets into one 15 centimeter and two 10 centimeter squares.For the top layer of...