List of Variables Recorded During STEPS Project with their corresponding Tag number

Parameters recorded or computed within the T-28 dataset are indexed with a tag number. This tag number is used to select data for the display in some of the SDSMT data analysis software.

Tag

Variable

Remarks

 

 

 

100

Time

The T-28 data system is set to UTC, and recorded in a 24-hour format for STEPS. It is set daily within a second of WWV, but suffers loss of a second or two each time system is booted.

 

 

 

101

Dynamic Pressure 1

 

 

 

 

102

Dynamic Pressure 2

Both dynamic pressures are read from the same pitot tube line (with the inlet out on the right wing) using two different but nearly identical sensors. [hPa]

 

 

 

103

Static Pressure 1

 

 

 

 

104

Static Pressure 2

Both static pressures are read from the same static pressure line (inlet on the rear fuselage) using two different but nearly identical sensors. [hPa]

 

 

 

105

Rate of Climb

Not usable during STEPS.

 

 

 

106

Rosemount Temperature

Computed from the reading of a standard, deiced, Rosemount aircraft total air temperature probe. It commonly suffers from wetting and reads low in clouds. [° C]

 

 

 

107

Reverse Flow Temperature

This is static temperature is computed from the reading of a platinum resistance element placed inside a custom-design "reverse-flow" housing. It normally does not get wet in clouds or in regions of high precipitation water concentration. Ice may sometimes build up to such an extent on the housing that airflow is changed and temperature readings are affected even though the sensor is not wetted. Its response to changes in angle of attack is greater than that of the Rosemount probe. [° C]

 

 

 

108

Manifold Pressure

Pressure inside the engine manifold (an indicator of power being developed by the engine) is recorded from a standard aircraft engine pressure sensor. [inches of mercury]

 

 

 

109

Acceleration

Vertical acceleration is determined by a Humphrey gyro-stabilized accelerometer. [gs]

 

 

 

110

Pitch

The accelerometer also gives angle of the fuselage relative to horizontal (positive for nose up). [deg]

 

 

 

111

Roll

The accelerometer also gives angle of the wings relative to horizontal. Angle is positive for a left bank (left wing down). [deg]

 

 

 

116

Voltage Regulator

Voltage of power source for some instruments. [volts]

 

 

 

118

NCAR True Airspeed

Airspeed computed by an analog circuit; can be used to clock PMS OAP-2D probes. Less accurate than "Calculated TAS", Tag 211

 

 

 

119

PMS End Element 1

Voltage readings of PMS OAP-2D probe end diodes. Used to monitor for fogging and icing of probe.

 

 

 

120

PMS End Element 2

 

 

 

 

121

Interior Temperature

Temperature inside the data acquisition system computer in the baggage bay. [° C]

     

123

High Voltage Current

High Voltage Current from the tail area of the plane.

 

 

 

124

Heater Current

Total current consumed by de-icing circuits (A).

 

 

 

130

Event Bits

Bits corresponding to various events recognized by the data system, including indications that the system is running, that the in-cloud switch is activated by the pilot (when visually entering cloud), and that the foil impactor is running.

 

 

 

131

GPS Warning Codes

Bits corresponding to various status messages from the GPS system.

 

 

 

140

FSSP size counts

This tag contains information concerning the number of counts in each of the 15 available FSSP size channels. [number per channel per second]

 

 

 

141

FSSP total counts

The total number of droplets counted by the FSSP during a second.

 

 

 

142

FSSP average diameter

The arithmetic average diameter of all droplets recorded during a second. [m m]

 

 

 

143

FSSP concentration

The number of droplets computed from FSSP counts divided by the volume sampled in 1 s. A rudimentary correction for probe activity is made. [# cm-3]

 

 

 

144

FSSP Water

The liquid water concentration computed from the FSSP data for a second. [g m-3]

 

 

 

145

FSSP Activity

The fraction of time the FSSP is logging particles during the current second.

 

 

 

147

2DC Total Shadow Or

Used to acquire the total shadow-or count for the 2DC probe. The total shadow-or count is the number of times the shadow-or output of the probe went active from the last time this data was acquired. [# s-1] The probe samples ~5 liters/s, so shadow-or count divided by 5 liters yields a rough estimate of small precipitation particle concentration.

 

 

 

148

FSSP Equivalent Diameter

deq = Also known in the radiation community as effective diameter.

 

 

 

149

Variance in FSSP Equivalent Diameter

Variance around the equivalent diameter, computed as 

     

150

Hail size counts

This tag contains information of the number of particles in each of the 14 hail spectrometer size

Channels. This tag is used by the DISPLAY program only. [number per channel per second]

     

151

Slow Particle

The number of particles rejected by the hail spectrometer counting circuitry because they

passed through the spectrometer too slowly (indicating they were probably water or ice shed from the probe structure rather than airborne hydrometeors). [number per second]

 

 

 

152

Hail total counts of (150)

Total number of particles accepted by the hail spectrometer. [number per second]

 

 

 

153

Hail average diameter

The average diameter of all particles accepted by the hail spectrometer in the last second. [cm]

 

 

 

154

Hail concentration

The computed concentration corresponding to all particles accepted by the hail spectrometer in the last second. [number per cubic meter]

 

 

 

155

Hail Water

The mass concentration computed from the observed particle spectrum assuming spherical particles and a bulk particle density of 0.9 grams per cubic centimeter. [grams per cubic meter]

 

 

 

160

Top Field Mill 

The electric field indicated by the low sensitivity channel on the field mill mounted in the aircraft canopy looking up. Field mill data are recorded at 20 Hz. [kV m-1]

 

 

 

161

Bottom Field Mill 

The electric field indicated by the low sensitivity channel on the field mill located in the baggage bay door looking down. [kV m-1]

 

 

 

162

Left Field Mill 

The electric field indicated by the low sensitivity channel on the field mill mounted in the left wing tip facing outward. [kV m-1]

 

 

 

163

Right Field Mill 

The electric field indicated by the low sensitivity channel on the field mill mounted in the right wing tip facing outward. [kV m-1]

 

 

 

168

Fifth Field Mill 

The electric field indicated by the low sensitivity channel on the fifth field mill, located forward in one of the hail spectrometer pylons under the left wing. [kV m-1]

169

Sixth Field Mill 

The electric field indicated by the low sensitivity channel on the 6th field mill, located aft in the same hail spectrometer pylon under the left wing (kV m-1)

 

 

 

170

HVPS Total Shadow Or

Did not work as expected during STEPS. [counts] 

     

171

HVPS Housekeeping Data

Stores the counts of the 8 housekeeping channels, which then can be converted in five window temperatures, two video voltages, and laser power readings, all being indicators of the probes proper functionality. This tag is used and displayed by the IDL program called READ_RAW.  

     

172

Latitude

Computed internally in the GPS receiver. [deg]

 

 

 

173

Longitude

Also computed internally in the GPS receiver. [deg]

 

 

 

174

Groundspeed

Computed internally in the GPS receiver (by differentiating position data with respect to time). [m/s]

 

 

 

175

Ground Track Angle

The direction towards which the aircraft is moving relative to the ground, with respect to magnetic north. [deg]

 

 

 

176

Magnetic Deviation

The difference between magnetic north and true north as indicated automatically by the GPS receiver based on the current position. [deg]

 

 

 

177

Time Since Solution

The time since the GPS was last able to compute an accurate position solution based on a sufficient number of satellites. The GPS updates position based on dead reckoning if it does not have a sufficient number of satellites in view. [s]

 

 

 

178

GPS Altitude

Geometric aircraft altitude. [m MSL]]

     

179

GPS Time

Time recorded from T-28 GPS receiver (UT)

     

185

GPS Rate Of Climb

Convert Rate of Climb from tenths of feet per minute to m/s.

     

186

DMT Liquid Water

DMT liquid water [g m-3].

     

187

DMT Slave

This tag is an indicator of the instrument performance. A voltage level of about 0 volts indicates that current is flowing through the slave coil. A + 5V level indicates that the slave coil has failed.

     

190

FSSP Gated Strobes

Number of accepted droplet counts. [# s-1]

 

 

 

191

FSSP Total Strobes

Total number of droplet counts. [# s-1]

 

 

 

192

FSSP Reference Voltage

Reference voltage for FSSP opto-electronics.

 

 

 

205

Altitude

The altitude in a standard atmosphere corresponding to the recorded static pressure. [m]

 

 

 

206

q e

The equivalent potential temperature corresponding to the recorded temperature and assuming saturation with respect to liquid water (should be valid in-cloud). [K]

 

 

 

207

Saturation Mixing Ratio

The mixing ratio of water vapor corresponding to saturation with respect to liquid water at the recorded temperature. [g kg-1]

 

 

 

208

Point dz/dt

The rate of change of altitude of the aircraft computed by differentiating the pressure altitude with respect to time.

 

 

 

209

Indicated Air Speed

What the true airspeed would be if the aircraft were flying at sea level and indicating the observed dynamic pressure. [m s-1]

 

 

 

210

Updraft (uncorrected)

The estimated upward speed of the air relative to the ground computed from changes in the aircraft altitude and other factors, but not corrected for horizontal aircraft acceleration. [m s-1]

 

 

 

211

Calculated TAS

The true speed of the aircraft relative to the air computed from the observed dynamic and static pressures, and temperature. [m s-1]

 

 

 

212

Updraft Correction Factor

A correction to tag 210, the simple (uncorrected) updraft calculation, that accounts for horizontal accelerations of the aircraft. [m s-1]

 

 

 

213

Cooper Updraft

The sum of the uncorrected updraft (210) and the correction factor (211). [m s-1]

 

 

 

214

Kopp Updraft

A more reliable updraft estimate calculated using methods discussed in Kopp, 1985. In most situations, it yields a less noisy and more physically plausible updraft result for the T-28 than the Cooper method. [m s-1]

 

 

 

216

Turbulence

The turbulent energy dissipation rate estimated from the spectrum of observed fluctuations in true airspeed following a method developed by MacCready. [cm2/3 s-1]

 

 

 

217

Air Density

Computed from the recorded temperature and static pressure. 

[kg m-3]

 

 

 

219

FSSP Mixing Ratio

The mixing ratio of cloud water per unit mass of dry air calculated from the FSSP water concentration. [g kg-1

 

 

 

220

Hail Mixing Ratio

The mixing ratio of hail mass per unit mass of dry air based on the computed hail water and air density. [g kg-1

     

221

RFT uncorrected

Stores the Reverse Flow Temperature uncorrected value.

 

 

 

244

FSSP equivalent J-W Liquid Water

An estimate of the liquid water concentration a J-W probe should record, based on the observed FSSP droplet spectrum and the assumption that a J-W probe responds incompletely to droplets larger than 30 m m diameter. This tag is provided only in the reduced data file. [g m-3]

 

 

 

260

Ambient Vert Electric Field

The component of the ambient electric field that is vertical in the aircraft frame of reference. Positive means a positive test charge would drift upward relative to the aircraft in the field. [kV m-1]

 

 

 

261

Vert Electric Field due to aircraft charge

The field due to charge on the aircraft, computed by summing the readings of the top and bottom mill and normalizing based on self-charging tests. Positive means a positive test charge would be repelled away from the aircraft due to its charge. [kV m-1

 

 

 

262

Ambient Hor Electric Field

The ambient field oriented perpendicular to the aircraft along the wings, positive meaning a positive test charge would drift to the left in the field. [kV m-1

 

 

 

263

Hor Electric Field due to aircraft charge

The field due to charge on the aircraft, computed by summing the wingtip mill readings and normalizing. Positive means a positive charge would be repelled away from the aircraft due to its charge. [kV m-1

 

 

 

264

Ambient Vert Field (roll cor)

The component of the ambient field that is truly vertical with respect to earth coordinates. [kV m-1

 

 

 

265

Ambient Hor Field (roll cor)

The component of the ambient field perpendicular to the aircraft path and truly horizontal with respect to earth coordinates. [kV m-1

266

Ex

X-component of ambient horizontal electric field, relative to the earth system, based on Mo et al (1999). Positive means a positive test charge would drift in the direction of the aircraft motion under the influence of the field.
[kV m-1]

 

 

 

267

Ey

Y-component of ambient horizontal electric field, relative to the earth system, based on Mo et al (1999). Positive means a positive test charge would drift to the left of the direction of the aircraft under the influence of the field. [kV m-1]

 

 

 

268

Ez

Z-component of ambient electric filed, relative to the earth system, based on Mo et al (1999). Positive means a positive test charge would drift upward under the influence of the field. [kV m-1]

     

269

Ey difference

Difference between tags 267 and 265.

     

270

Ez difference

Difference between tags 268 and 264.

 

 

 

272

Latitude (deg)

GPS coordinates broken into separate degree and minute components.

 

 

 

273

Latitude (min)

GPS coordinates broken into separate degree and minute components.

 

 

 

274

Longitude (deg)

GPS coordinates broken into separate degree and minute components.

 

 

 

275

Longitude (min)

GPS coordinates broken into separate degree and minute components.

 

 

 

276

Ground Track Angle (True N)

The direction of motion relative to the ground with respect to true north, derived from the GPS ground track angle with respect to magnetic north. [deg]

 

 

 

290

X-acceleration

Acceleration in the direction of aircraft motion. Acceleration backward (deceleration) yields a positive value. [g's]

 

 

 

291

Y-acceleration

Acceleration perpendicular to the direction of aircraft motion, along the direction of the wings. Acceleration toward the left yields a positive value. [g's]

 

 

 

292

Z-acceleration

Vertical acceleration. Upward acceleration produces a positive value. [g's]