• Project: SARPEC-IOP2 - Saudi Arabia AeRosol-Cloud-Precipitation Enhancement Campaign (SARPEC) IOP2
• Dates: October 18 2023 - November 29 2023
• Location: Central Saudi Arabia (Fall 2023)
• Platform: North Dakota Citation Research Aircraft
• Tail Number: N555DS
• Aircraft Base: Thumamah Airport (OETH)
• Flight Level Processing Script: process_all_saudi2023

• WMI Project Portal (Password Required): https://www.wmiradar.com/ksa
• SARPEC-IOP2 Atmospheric Sciences Field Catalog
• SARPEC-IOP2 Aerospace College Field Catalog

Table 1: Listing the time segments for use to calibration the Citation Research Aircraft Winds System. The capital letter in the Flight ID indicate altitude level, the lower case letter indicates the maneuver type and number indicates the segment.

On 27 October 2023 there are four cloud cores sampled, which are labeled A, B, C, and D. Cloud A, B, C are sampled at multiple altitudes, which core D is sampled at a single altitude. All clouds are were not seeded with AgI.

The 27 October 2023 Flight Engineer Report indicates that aircraft descending to 19.5 kft at 11:01 UTC to sample clouds at the -10 ºC level. A 19.5 kft sample is conducted at 11:12 (40,320 sfm) UTC. After missing the cloud at 11:14 pass, the same clouds is sampled at 11:16 (40,560) UTC at 21.0 kft. Hence, there are two passes of cloud 20231027A. A new clouds is located at 11:23 UTC. Cloud 20231027B is sampled at 22 kft at 11:33 (41,580 sfm) UTC, at 23 kft at 11:37 (41,820) UTC, and at 24 kft at 11:42 (42120) UTC.

Table 2: Listing of the time segments during sampling of convective cloud cores A and B. The letter in the Flight ID indicate cloud label and number indicate pass on the cloud. The Pressure Altitude if from the aircraft's pilot reports recorded in flight notes. The air temperature is from 1 Hz Wing Probe Rosemount temperature probe data contained in the project's science file. Lynnlee Rosolino determine the core sampling times for cloud 20231027A and cloud 20231027B.

The 27 October 2023 Flight Engineer Report indicates that aircraft descending to 20.0 kft at 11:48 UTC to sample clouds at the -10 ºC level. First pass on cloud C at 11:55 (42,900 sfm) UTC, which has AIMMS issue resulting in the need for a power cycle. Second pass at 22 kft at 11:58 (43,080 sfm) and third pass at 23 kft at 12:04 (43,440 sfm). Hence, there are three passes of cloud 20231027B. A new clouds is sampled at 12:08 (43,680 sfm) UTC at 20 kft before returning to base due to low fuel and too late in the day.

Table 3: Listing of the time segments during sampling of convective cloud cores C and D. The letter in the Flight ID indicate cloud label and number indicate pass on the cloud. The Pressure Altitude if from the aircraft's pilot reports recorded in flight notes. The air temperature is from 1 Hz Wing Probe Rosemount temperature probe data contained in the project's science file. Valeria Garcia determine the core sampling times for cloud 20231027C and cloud 20231027D.

———– Note:the cloud below (sampled at 11:58 UTC) is not the same cloud sampled above at 11:33 & 11:38 UTC

On 28 October 2023 there are four cloud cores sampled, which are labeled E, F, G, and H, each sampled at multiple altitudes. All clouds cores are were not seeded with AgI.

Table 4: Listing of time segments during sampling of convective cloud cores E and F. The letter in the Flight ID indicate cloud label and number indicate pass on the cloud. The Pressure Altitude if from the aircraft's pilot reports recorded in flight notes. The air temperature is from 1 Hz Wing Probe Rosemount temperature probe data contained in the project's science file. James Klinman determine the core sampling times for cloud 20231028E and cloud 20231029F.

Figure 1: Image taken on 28 October 2023 flight at 10:58:45 (39,525 sfm) UTC showing the convective cumulus cloud before sampling by the North Dakota Citation Research Aircraft. Picking such a cloud target to sample takes experience as there are many items to consider. Specifically, the considerations for selecting a cloud target includes; cloud liquid water, cloud updraft, lack of cloud ice, cloud bulk size, cloud temperature (cold), and cloud structure (low and solid cloud base). For isolated convective cumulus clouds, there has to be visible growth as indicated by the edges of the cloud increases with time. The cloud needs to not show signs of ice development by have sharp, well defined edges with a “hard tops”. The cloud base should be solid and the cloud depth should be 6-8 kft. The cloud lifetime should be approximately 15-30 minutes. The cloud may, or may not, be sheared. For multiple cellular clouds, the sampling is more complete. There are new cells that develop close to the mature storms, which are called “feeder cells”. If such turrets show visible growth, they can be targeted for sampling or cloud seeding. Typically, the feeder cells develop, mature and merge into the larger storm complex. Aircraft operations around such multi-cell storms are more complex as it is necessary to avoid the large storm which may contain hail, lightning and large updraft or downdrafts.

Table 5: Listing of time segments during sampling of convective cloud cores G and H. The letter in the Flight ID indicate cloud label and number indicate pass on the cloud. The Pressure Altitude if from the aircraft's pilot reports recorded in flight notes. The air temperature is from 1 Hz Wing Probe Rosemount temperature probe data contained in the project's science file. James Klinman determine the core sampling times for cloud 20231028G and cloud 20231028F.

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