List of Variables Recorded During Greeley 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. [g’s]
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. [mm]
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]