**SMOS**

**SIX-MONTH CALIBRATION PROCEDURES**

**Facility: EF**

**Frequency: Twice a year**

**Mentor: Michael Ritsche**

**NOTE: Prior to all testing and verification, Flag 7 must be set high
to prevent false data from being recorded. This Flag should be reset
when complete.**

**1. 05103 RM Young Wind Monitor**

> A. Wind speed
>
> To check that the wind speed sensor is measuring properly, the
> following equipment is needed.

1\. 9/16\" wrench

2\. #18810 Anemometer drive

3\. A computer or CR10KD

4\. Two people

> Tilt the tower down to access the wind monitor. Refer to Appendix C
> for Tower lowering procedure. Remove the propeller from the propeller
> shaft and install the torque nut provided. The anemometer drive
> connects to the wind monitor body and the motor connects to the torque
> nut. Next, select one of the following RPM levels on the anemometer
> drive and start the unit. Wait for the RPM level to stabilize.

[RPM]{.underline} [RPM Reading]{.underline}

500 \_\_\_\_\_\_\_\_\_\_\_

750 \_\_\_\_\_\_\_\_\_\_\_

1000 \_\_\_\_\_\_\_\_\_\_\_

> Compare the reading from the anemometer drive and the sensor output as
> read from the computer or the CR10KD. The RPM's measured by the CR10
> (Location 10) should be within +/- 1% of that indicated in the above
> table.
>
> B. Wind Direction
>
> Using the angle fixture and a computer or a CR10KD, check that the
> sensor output (Location 2) matches the direction settings determined
> by the angle fixture #18212. The angle fixture is inserted between the
> orientation ring and the wind monitor. Once the angle fixture is
> installed, make sure that the notches of the orientation ring, angle
> fixture and wind monitor all match up. Use the positioning arm to hold
> the tail of the wind monitor in the correct position. Rotate the wind
> monitor through the positions listed below and compare them to
> directions measured by the data logger (Location 2).

Quadrant Measured value

0 \_\_\_\_\_\_\_\_\_\_\_

90 \_\_\_\_\_\_\_\_\_\_\_

180 \_\_\_\_\_\_\_\_\_\_\_

270 \_\_\_\_\_\_\_\_\_\_\_

355 \_\_\_\_\_\_\_\_\_\_\_

> The accuracy of this measurement is +/- 5.0 degrees, with a resolution
> of 1.0 degree.
>
> **NOTE:** **The absolute accuracy of this measurement depends on the
> exactness of the orientation of the sensor with respect to true
> north**.

**2. HMP-35C Temperature & Relative Humidity**

To verify the accuracy and installation of the HMP-35C sensor the
following tools will be needed.

1\. HMI31/HMP35 Temperature and Relative Humidity

> Meter, recently calibrated.

2.  Computer or CR10KD

3.  Portable Aspiration Unit.

Remove the sensor from the radiation shield and inspect, clean or
replace the humidity cap. Verify that the sensor is working properly
using the following procedures.

> The verification of the temperature sensor is done with the Vaisala
> HMI31/HMP35 T/RH meter. Mount the portable aspiration unit on the SMOS
> tower approximately chest high. Place the HMP-35C T/RH sensor and the
> HMI31/HMP35 T/RH Meter in the holders of the portable aspiration unit.
> Turn on the HMI31/HMP35 meter. Allow the sensors to stabilize such
> that the temperature and RH readings are changing by less that +/- 0.2
> Deg C or +/- 1% RH, then wait another 5 minutes before taking
> readings. The air temperature measurement is stored in the data logger
> in location 3 and the RH readings are stored in location 4. You can
> monitor this location with either a computer or the CR10KD. Compare
> the data logger measurement to the read-out of the HMI31/HMP35. The
> temperature readings should match within +/- 0.5 C. The resolution of
> the data logger measurement is 0.01 C. The RH readings should match
> within +/- 2 % RH from 0 - 90 % RH or +/- 3 % RH from 90 - 100 % RH.
> The resolution of the data logger measurement is 1.0 % RH.
>
> If the Bi-weekly check is being done at the Central Facility the
> portable aspirator is not needed. The SMOS site at the Central
> Facility has an aspirated shield. The HMI31/HMP35 Meter may be held
> near the intake of the aspirated shield. Take care to position the
> HMI31/HMP35 T/RH meter out of direct sunlight.
>
> **[NOTE]{.underline}:** If the probe or the T/RH Meter has been
> exposed to a temperature significantly different from the ambient air
> temperature and RH, it may take an appreciable time for the sensor to
> stabilize. They may require rapid waving before they will stabilize.

Test Results:

[Measurement]{.underline} [Cal Standard]{.underline} [SMOS
Sensor]{.underline} [Pass/Fail]{.underline}

Temperature \_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_

Humidity \_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_

**3. UDG01 Snow Depth Gauge (CURRENTLY NOT DONE)**

**NOTE: The grass or vegetation under the gauge should be cut short and
kept manicured to obtain accurate snow depth readings.**

To start this test set Flag 8 high. This is done either using the F8 key
while monitoring the input locations in PC208W or using the CR10KD. To
use the CR10KD press **\*6AD8** to set the flag. The flag will
automatically reset in two minutes. Once Flag 8 is high the UDG01 snow
depth gauge will start making measurements once per second for two
minutes. The snow depth measurement is found in location 17 in the data
logger, this measurement should be within +/- 25 mm of zero when nothing
is under the snow depth gauge. The snow depth gauge has a resolution of
0.5 mm. A cardboard box of a known height at least 2 feet by 2 feet
square is then placed under the gauge. The measurement with the box
under the gauge should show the height of the box within +/- 25 mm.

**4. 2500E Rain/Snow Gauge**

Two things need to be verified on this sensor. The first is that the
sensor records each tip of the bucket, and the other is to check that
the heater portion of the rain gauge functions.

> A. Rain fall
>
> The rainfall verification is accomplished with the 500 milliliter
> volumetric flask and plastic cup provided with the system.
>
> **Note this test should be started just after the even hour to insure
> that the system does not reset the number of counts during the test
> (This location resets every two hours).**
>
> Fill the volumetric flask to the indicator line and place the plastic
> cup in the top of the rain gauge. Pour the 500 ml of water into the
> cup and allow the contents to slowly drain through the rain/snow
> gauge. Using the data logger to measure the counts of the rain gauge
> the number of tips for 500 ml of water should be 25 to 27 counts; this
> value is stored in Location 16. This test requires that the amount of
> water used is precisely 500 ml. Once most of the water has drained
> from the cup, slowly pour the last of the water through the rain
> gauge.
>
> B. Heater
>
> To verify the operation of the heater in the rain/snow gauge, the
> following test should be performed. Place an ice cube in a plastic bag
> and hold the ice on the thermostat for 1 minute, and continue to hold
> in place while checking the heater (See Rain Gauge Manual in
> Installation Manual). Feel the heater element at the base of the rain
> gauge and ensure that it has started to get hot. The heater should be
> warm to the touch within 30 to 45 seconds after the thermostat has
> been tripped; the thermostat is set to trip at 37 degrees F.

**5. PTB-201 Barometric** **Pressure**

The PTB-201 barometer is located inside of the enclosure. A computer or
the CR10KD can be used to monitor the location where the barometric
pressure is being displayed (LOC: 18). Establish communications with the
data logger and monitor location 18 for barometric pressure in
millibars. Use the PTB-220 Digital Barometric pressure transducer to
read the current barometric pressure in millibars and compare the two
values. The two values should be with in +/- 0.5 millibars of each
other; the resolution of the sensor is 0.1 millibars. The barometric
pressure that is measured and recorded in the station (Location 8) is in
Kilopascals and

is 1/10 of the millibars readings used in the verification of the
sensor.

**SURFACE METEOROLOGICAL OBSERVATION SYSTEM**

**SENSOR VERIFICATION FORM**

**SITE ID:\_\_\_\_\_\_\_\_\_\_\_\_\_
LOCATION:\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_**

**Tested by:\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
Date:\_\_\_\_\_/\_\_\_\_\_/\_\_\_\_\_**

**Started: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_GMT Ended:
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_GMT**

**1. 05103 Wind Monitor**

**A. Wind Speed**

**[RPM]{.underline}** **[Measured RPM]{.underline}** (LOC: 10)
**[PASS/FAIL]{.underline}**

**500** \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

**750** \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

**1000** \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

The measured RPM should be within +/- 1% of the motor drive RPM.

**Acceptable: YES / NO**

**B. Wind Direction**

**[Quadrant]{.underline}** **[Measured value]{.underline}** (LOC: 2)
**[PASS/FAIL]{.underline}**

0 \_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

90 \_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

180 \_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

270 \_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

355 \_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_

The accuracy of this measurement is +/- 5.0 degrees, with a resolution
of 1.0 degree.

**Acceptable: YES / NO**

**2. HMP-35C Temperature & Relative Humidity**

**[Measurement]{.underline} [Cal Standard]{.underline} [SMOS
Sensor]{.underline} [Pass/Fail]{.underline}**

**Temperature \_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_**

**Humidity \_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_**

(Temperature readings are in LOC: 3, RH in LOC:4)

The temp readings once stabilized should match within +/- 0.5 C. The
resolution of the data logger measurement is 0.01 C.

The RH readings once stabilized should match within +/- 2 % RH from 0 -
90 % RH, +/- 3 % RH from 90 - 100 % RH. The resolution of the
measurement is 1.0 % RH.

**Acceptable: YES / NO**

**3. UDG01 Snow Depth Gauge (not done at this time)**

(LOC: 17)

**Object Height Measured**:\_\_\_\_\_\_\_\_\_\_
**UDG01**:\_\_\_\_\_\_\_\_\_\_\_\_\_\_

This measurement should be within +/- 25 mm.

**Acceptable: YES / NO**

**4. 2500E Rain/Snow Gauge**

**A. Rain, 500 ml should produce 25 to 27 tips**

**Number of tips recorded**:\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ (LOC: 16)

**Acceptable: YES / NO**

**B. Heater**

**Acceptable: YES / NO**

**5. Barometric Pressure**

**PTB-220 Reading:\_\_\_\_\_\_\_\_\_\_\_\_**

**PTB-201 Reading:\_\_\_\_\_\_\_\_\_\_\_\_** (LOC: 8)

The readings should agree within +/- 0.05 kPa or 0.5 mb.

**Acceptable: YES / NO**

**6. Comments:**