Studying Water in Motion

Transcription

1 Studying Water in Motion Firstname Lastname Department Institution City, State, ZIP ABSTRACT Placeholder. 1. INTRODUCTION 2. DESIGN GOALS How polluted is the RF spectrum? Are there other radios operating nearby? If so, in what bands and which frequencies? How will the sensors be physically secured? Will they be mounted to PVC, aluminum, or steel tubes? How soft is the ground? No data gaps. No manual configuration. Minimize coupling between different node types. Use a mesh network, like Roofnet, for the backbone. 3. SITE SURVEY On June 5th and 6th, 2006, we performed a site survey of XYZ. The purpose of the survey was to answer a variety of questions pertinent to our deployment: What is the name of the site? What is the latitude, longitude, and altitude of the site? What are the temperature extremes obeserved over the course of a year? Is there canopy cover? If there is no canopy cover, what is the zenith angle to the surrounding tree tops? What is the surrounding foliage and canopy like? Will they encroach upon the site? What are the details of the network connection available at the site, including type, speed, reliability, connection interface, shared vs dedicated. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Copyright 200X ACM X-XXXXX-XX-X/XX/XX...$5.00.

2 4. SENSOR SUITE

3 Table 1: Sensor Details. Phenomena Sensor Range Accuracy Resolution Interface Cost V cc I on I sleep T read Humidity Sensirion SHT %RH ±3.5 5 %RH 0.03 %RH (12 bit) 2-wire digital V 550 µa 1 µa 51 ms Temperature Sensirion SHT ± (14 bit) 2-wire digital V 550 µa 1 µa 51 ms Pressure Intersema MS5534A mbar ±1.5 mbar 0.1 mbar (15 bit) 3-wire digital V 1 ma 3.5 µa 35 ms TSR Hamamatsu S lx n/a ADC dep. analog n/a A n/a 35 µs (1) PAR Hamamatsu S lx n/a ADC dep. analog n/a A n/a 35 µs (1) Soil Moisure Decagon EC % VWC ±4% m 3 /m 3 analog V 3 ma 10 ms Sap Flow ICT International cm 3 cm 2 /Hr TBD TBD Monibus 12 V 667 ma 2.5 s Precipitation Vaisala RAINCAP mm/hr 5 % 0.01 mm SDI-12, RS-xxx 5 30 V 3 ma (2,3) 70 µa 250 ms Wind speed Vaisala WINDCAP 0 60 m/s ±0.3 m/s 0.1 m/s SDI-12, RS-xxx V (4) 3 ma (2,3) 70 µa 250 ms Wind direction Vaisala WINDCAP ±2 1 SDI-12, RS-xxx 5 30 V 3 ma (2,3) 70 µa 250 ms Isotope T read = T wake + T sense (1) Assuming a 100 KΩ load resistance. (2) Assumes a default sample rate of 4Hz. (3) Heating element (opt.) cleans snow/ice but draws more current. (4) Below 5.3 V, measurement for high wind diminished.

4 5. ASSUMPTIONS This section list our current assumptions. 5.1 Deployment Stages System rollout will happen in stages: (i) desktop demo, (ii) overnight outdoor demo, (iii) Strawberry Canyon minideployment, (iv) Elder Creek mini-deployment, (v) Elder Creek and Sagehen Creek winter mini-deployments, (vi) Elder Creek single-patch deployment.

5 6. DEPLOYMENT PLAN This section summarizes the current deployments plans for academic year Stages The HydroWatch system will follow a staged deployment plan to maximize learning in the lab and minimize it in the field. The deployment stages are detailed in Table 6.1. A number of smallscale trials will be conducted prior to these stages to test individual system components (e.g. power, sensors, networking, and storage). Table 2: Details of currently planned deployment stages. Stage Location Nodes Dates (MMDDYY) I Berkeley 42 07/01/06 09/30/06 II Elder Creek 44 10/01/06 03/31/07 III Sagehen 44 03/01/07 06/30/07 In addition to the Level 1 data, Stage II will produce a large corpus of system performance data including link quality and network connectivity statistics, packet delivery success and failure, and energy availability and variability. The volume of system performance data is a function of random variables like network reliability, weather variability, andr depth in the routing tree, and hence is difficult to predict precisely. Both the sensor data and the system data will be durably logged on each node and collected either via a multihop wireless network, through direct wireless interrogation, or by a physical connection and log readout, in descending order of preference. 6.3 Geometry The Stage II deployment geometry will be a subset of a transect perpendicular to the stream and located near the mouth of Elder Creek, as shown in Figure 6.3. This location, near the bottom of the watershed, was chosen because it is easy to access and instrument. The node layout in this transect is shown in Figure 6.3. Note: Stage III is only executed if the schedule slips such that nodes cannot be installed in Elder Creek during the Stage II timeframe. The goal of Stage I is to evaluate system integration and operation at a scale representative of an actual deployment. The twin goals of Stage II are to collect scientifically-relevant data and evaluate system performance in an actual deployment. Stage III is a fallback plan in case schedule slips cause us to miss the deployment window for Elder Creek in Each stage will incorporate lessons from the earlier stages. 6.2 Data Collection The data collected during Stage I will allow us to evaluate the system but will not yield data of scientific value to the HydroWatch project. However, the collected data will allow us to sanity-check the sensor readings and corroborate expected correlations between sensors. The isotope sensor will not be deployed in Stage I and may not be ready until after Stage II. The Level 1 data collection and storage targets for Stage II are listed in Table 6.2. Level 1 data are raw, point-wise measurements reported in the units of the instrument (e.g. volts, counts), along with data identifiers (timestamp, latitude, longitude, altitude, nodeid). The data yield objective is 100% and threshold is 90%. Figure 1: The yellow triangle marks the target deployment zone. The red outline along the ridge marks the perimeter of the Elder Creek watershed. The watershed covers 17 km 2, is 7 km long, has an elevation of 400 m to 1200 m, receives strongly-season annual rainfall of 2000 m, and is a steep, landslide-prone topography with boulder-covered channels in narrow canyons. Table 3: Stage II sensing and storage details. Quan Node/Sensor T sample Samples Storage 16 Climate 1,310, MB Temperature 1 min 262, KB Humidity 1 min 262, KB Pressure 1 min 262, KB TSR 1 min 262, KB PAR 1 min 262, KB 16 Soil Moisture 5 min 52,416 TBD 8 Sap Flow 30 min 8,736 TBD 2 Weather Precipitation TBD TBD TBD Wind vector 1 sec 31,449,600 TBD Temperature 1 sec 15,724,800 TBD Humidity 1 sec 15,724,800 TBD Note: The 1 sec samples from the Weather node will be combined, averaged, and stored at a 1 min resolution. Figure 2: The node layout for the Stage II deployment. The 16 Climate nodes are mounted above and below the canopy on eight trees. The 16 Soil Moisture nodes are mounted across the transect at various depths (TBD) and positions in and around the creek bed. The eight Sap Flow nodes are mounted to the same eight trees as the Climate sensors. Two weather nodes are mounted on two of the eight trees instrumented for Climate.

6 7. OPEN QUESTIONS This sections lists questions and answers which have surfaced during the course of this project. 7.1 Site Survey What is the name of the site? There are two sites, Elder Creek (near Branscomb, CA) and Sagehen (near Truckee, CA). What is the latitude, longitude, and altitude of the site? TBD What are the temperature extremes obeserved over the course of a year? Elder Creek does not freeze. Sagehen gets between 5 ft and ft of snow. Is there canopy cover? Elder Creek has a dense canopy with very few openings. Sagehen has a sparser canopy with more openings. If there is no canopy cover, what is the zenith angle to the surrounding tree tops? There is canopy cover. What is the surrounding foliage and canopy like? Will they encroach upon the site? The surrounding areas includes scrub brush, fallen trees, and steep terrain. 7.2 Network What are the details of the network connection available at the site, including type, capacity, availability, reliability, coverage, connection interface, attachment points, shared vs dedicated. There is an OC-3 connection (155 Mbps) available on Cahto Peak. A much slower backbone network is being assembled by Collin Bode. This backbone will be constructed using radio repeaters placed on ridge lines at points with a clear LOS to Cahto Peak. The connection to the patch needs to worked out. Can the existing Sagehen wireless data infrastructure be used for the HydroWatch project? If so, what is the availability, capacity, and coverage of this network, and what/where are the network attachment points? TBD How polluted is the RF spectrum? Are there other radios operating nearby? If so, in what bands and which frequencies? The spectrum is clean. 7.3 Sensors What is the size and shape of the sensor patch? See Deployment Plan. How many sensor patches will exist in total? See Deployment Plan. What is the breakdown of nodes in the sensor patch? See Deployment Plan. Which sensor(s) will measure atmospheric water vapor? Atmospheric water vapor is the same thing as relative humidity. Is sensor calibration necessary? How will calibration be performed? Who will do it? Yes, calibration is necessary. Todd Dawson s lab has a growth chamber and his group will assist with this process. Will readings be delivered in raw values (e.g. counts, voltage) or scientific units? Where will the conversion be performed? Data will be delivered in raw values and converted into scientific units at the data center. How should the temperature, pressure, and humidity sensors be exposed to the environment? T, P, and H sensors should be open to the environment but wellshielded from direct sunlight. Consult with Todd Dawson about this requirement. Should the TSR and PAR sensors be directly exposed to the environment or should there be a protective cover over it? There should be some kind of protective cover/dome to ensure water does not collect on the sensors. How will we ensure that the TSR and PAR sensors are leveled? Do we need some kind of leveling screws? The sensors will be leveled when mounted to the trees. Todd Dawson s group will provide guidance on the mounting details. Is alignment important (e.g. the node should point North)? If the TSR and PAR sensors should be directly exposed, is condensation on the sensors a problem? If so, is a protective cover (e.g. K5 glass domes) required? Yes, to ensure that wind direction is relative to a particular heading. Is cosine correction applied to the raw TSR and PAR sensor readings or does there need to be mechnical support (e.g. an aspheric lens or diffuser)? Cosine correction is applied to the reading in the data center. How tightly do the nodes need to be time synchronized, both relatively and absolutely?

7 The wind/temp/rh sensors require 1 second synchronization while all other sensors need to be synchronized to 1 minute. How accurately do the node positions need to be known, both relatively and absolutely? How will this be done? 1 meter. Nodes location will be noted during deployment. How will the sensors be physically secured? Will they be mounted to PVC, aluminum, or steel tubes? How soft is the ground? See Deployment Plans. 7.4 Packaging Does the packaging need to be waterproof and floodresistant? TBD 7.5 Mote Network Will external antennas be needed? sensors be located? How far apart will the TBD. Almost all radios will be located above ground. What is the impact of radio frequency (433 MHz, 916 MHz, 2.4 GHz) on range in the the environment? TBD. Need to run trials. 7.6 Solar Availability What is the typical harvestable solar power delivery to the nodes? Estimate is approximately 1%. Running solar cells to above the canopy is ill-advised because (i) high cost, (ii) critters want to chew the wires, and (iii) perceived lower reliability of long wire runs. We need to get sample data from the environment. 7.7 Deployment Lessons What went well with earlier deployments like the Redwoods? What could have gone better with earlier deployments? Several things: (i) data visualization/analysis could have occurred faster, allowing immediate feedback; (ii) the data logs were too small and data were lost; (iii) some nodes were broken and it was difficult to determine this in the field; (iv) the overall data yield was lower than desired. What would the ideal deployment experience be like? 8. REFERENCES