NevCAN: Nevada Climate-ecohydrological Assessment Network

University of Nevada, Reno (UNR); Desert Research Institute (DRI), University of Nevada, Las Vegas (UNLV)

Figure Caption: Typical equipment deployment on the NevCAN sites, including IP-compatible dataloggers, webcams, power relays, and solar chargers.

Problem

Several “full-service” climate stations were installed for purposes of establishing long-term baseline environmental monitoring across the full elevational gradient in two separate mountain ranges in the Great Basin region, North America. These stations monitor meteorological, ecological, hydrological, and pedological parameters at time frequencies ranging from 10 Hz (eddy covariance) to 1 hour (site imagery). Site settings range from Mojave desert at 800 m elevation to Subalpine forest at 3300 m elevation. All stations are off-grid, remote installations on private and public lands, a minimum of 1 hour travel time from a servicing institution, with the average travel time being 6 hours. Stations are designed to provide property, power, and connectivity for baseline services as well as experimental additions. Data acquired at the stations need to be transferred to the Nevada Climate Change Portal (project Cyberinfrastructure developing data center) at UNR, and the Western Regional Climate Center (WRCC) at the Desert Research Institute-North (DRI-North).

Data acquisition options (planning)

Possible pathways for data acquisition for NevCAN include: 1) onsite technician download (seasonal); 2) unidirectional telemetry via NOAA GOES satellite; 3) bidirectional transmission via internet connectivity at local cell towers, commercial local Internet Service Providers (ISP’s), satellite Internet providers, or collaborative partners at Great Basin College (GBC), Nevada Seismological Laboratory (NSL), University of Nevada, Las Vegas (UNLV), Desert Research Institute-South (DRI-South).

Decision

NevCAN designers decided to implement a hybrid approach using all three methods, in order to diversify data flow for reliability purposes.

Final Implementation

Manual download

All stations are configured to allow local manual download via direct logger connections or local ethernet connection over the field subnet. Technicians download files in CSI XML format for later transfer to data center on an as-needed basis.

Unidirectional transmission

Stations in less-accessible locations (high-elevation) have NOAA GOES satellite transmitters installed as part of the meteorological subsystem, sending a subset of hourly data (70 values) to the Western Regional Climate Center (WRCC) where they are processed and made available for transfer to the C.I. data center.

Bidirectional transmission

All stations are interconnected using a terrestrial wireless IP network organized into locality-specific private subnets. Traffic between private subnets is managed via OSPF routing protocols over both wireless radio connections and VPN tunnels between internet-connection points. Points of internet connectivity on each subnet are connected to C.I. private subnets via VPN tunnels and OSPF protocols. Acquisition software connections from C.I. servers to field loggers and devices is real-time and seamless over these networking paths.

Figure Caption: Map of IP communication paths for NevCAN

Hardware/process solutions

Manual download

Field laptop connections via ethernet, USB, or RS-232 protocols to portable flash memory

Unidirectional transmission

Campbell Scientific GOES TX system connected to CR3000 meteorological datalogger, WRCC GOES data import process and ASCII file export

Bidirectional transmission

Field internet connection points - Great Basin College campus, Nevada Seismological Laboratory field network, commercial ISP
Backbone field IP radios

AFAR Communications transparent TCP/IP bridge radios over 2.4 GHz (LoS) and 900 MHz (nLoS) ISM bands; antennas optimized for each link application; 10 Mbps network speed typical

Secondary IP radios - 5.x GHz Mikrotik Metal and Sextant router/radios, antennas optimized for link applications; 30 Mbps network speed typical
Onsite switching - ICP-DAS NS-208 industrial 8-port DC switches
Routing - Mikrotik RB433, RB493, and RB1100 routers at all subnet junctions
Ethernet Interfaces - Campbell NL115, Campbell NL100, Campbell NL200, direct connection if devices are IP enabled
Misc support hardware - low voltage disconnects, IP relays, ethernet surge protectors, shielded CAT5e and connectors
Repeaters/relays - standalone relay/repeater system with solar power/AFAR radio at 3300 m elevation; purchased rackspace/towerspace with Nevada Department of Information Technology for mountaintop hub/relay on grid/commercial power

Figure Caption: Standalone radio relay at 3300 m elevation

Personnel/expertise solutions

Field electronics/datalogger/sensor subsystem specialists
GOES satellite approved data technician
IP network architect and administrator
Terrestrial RF network architect and technician
Field construction/fabrication technician

ProTips

Short coaxial runs (install radios on towers near antennas)
Weatherproofing connectors (Coax Seal wrapped with Scotch 33+ electrical tape)
Black non-metallic paint on antenna panels and radomes accelerates de-icing
RF spectrum surveys on-site help identify potential interference issues
LVD-protected, redundant solar/battery systems increase high-elevation reliability
Standardized per-site IP addressing schemes critical for scalability
Dedicated comms enclosure for DIN-mounted power distribution and device mounting
Use outdoor, UV-jacketed, shielded CATx cable