Saito Research Group - TAMUoic2019

1. General

This is a database of the single-scattering properties of oriented ice crystals (OIC). The two major oriented particles, horizontally oriented plates (HOP) and columns (HOC), are considered in the database. The organization of this database is described in the ReadMe file. To download the database, see Section 5 below.

Lead developer: Dr. Masanori Saito (msaito [at] uwyo.edu)

PI: Dr. Ping Yang

Reference:

1). Saito, M., and P. Yang, Oriented ice crystals: A single-scattering property database for applications to lidar and optical phenomenon simulations, J. Atmos. Sci., 76, 2635–2652.

2. History

(MM/DD/YYYY) (Author) (Note)

02/01/2018 Masa Saito Project initiated.

12/10/2018 Masa Saito Oriented plate completed.

03/01/2018 Masa Saito Oriented column completed.

07/10/2019 Masa Saito Released as version 1.0

04/18/2021 Masa Saito Encoder and kernel techniques implemented.

04/27/2021 Masa Saito Released as version 1.1

05/08/2023 Masa Saito Note on potential bugs in the database

3. Overview of the Database

The TAMUoic2019 database covers sufficient range of particle sizes at three lidar wavelengths (355, 532, and 1064 nm), particle morphologies, and the refractive indices as follows:

Particle habit: HOP and HOC (2 habits)
Wavelength: 355, 532, and 1064 nm (3 bins)
Maximum diameter: 50–10,000 µm (165 bins)
Incident polar angle: 0°–90° (94 bins)
Scattering polar angle: 0°–180° (498 bins)
Scattering azimuthal angle: 0°–358° (180 bins)
Full phase matrix elements: (16 elements; P11, P12, P13, ... P44)

The maximum diameter, incident polar angle, and scattering polar angle have inhomogeneous bin-intervals. While the scattering azimuthal angle has homogeneous interval of 2°. This database is useful for lidar applications and optical phenomenon simulations (see Saito and Yang, 2019).

Note

There is a caveat on the database usage if you apply this database for radiative transfer simulations at quasi-forward scattering angles. For the cases with the incident polar angle is 0°, P11 at the forward scattering angle is inaccurate due to misplacement of the original data. Other data are accurate.

Figure 1. An illustration of assumed ice crystal shape (i.e., HOP and HOC) and examples of their 2D phase function.

4. TAMUoic2019 encoder

The version 1.1 of the TAMUoic2019 database includes the data kernel (~500GB) and encoder. The encoder converts the data kernel with the binary format into human-readable ASCII format of the database. A user can specify the maximum diameter bins, incident polar angle bins, and wavelength bins for the conversion. As the total data size of the TAMUoic2019 database can be huge (1.8 TB with the ASCII format), a user can reduce the size of the ASCII database with specifying a limited number of bins in the input file for encoding. A database of a single habit, a single maximum diameter, a single incident polar angle, and a single wavelength with the ASCII format has the total data size of approximately 22MB.

A user needs to specify the following information in the input file:

maximum diameter bins and bin size ("siz" and "nsiz")
incident polar angle bins and bin size ("iang" and "niang")
wavelength bins and bin size ("wav" and "nwav")
particle habit ("hab"; 14 characters): "Oriented Plate" or "OrientedColumn"

Then, type the following command to encode the ASCII format of the TAMUoic2019 database:

$ ./tamuoic2019encode {input_file}

5. Code & Data Availability

The TAMUoic2019 database consists of the data kernel and database encoder (.f90). The database is available at:

Baseline "Scaler" TAMUoic2019 Version 1.1.0 (https://doi.org/10.5281/zenodo.4718022)
Data kernel extensions for the "Vector" TAMUoic2019 database
- P12 kernel extension (https://doi.org/10.5281/zenodo.4740630)
- P13 kernel extension (https://doi.org/10.5281/zenodo.4741257)
- P14 kernel extension (https://doi.org/10.5281/zenodo.4741351)
- P21 kernel extension (https://doi.org/10.5281/zenodo.4732353)
- P22 kernel extension (https://doi.org/10.5281/zenodo.4732272)
- P23 kernel extension (https://doi.org/10.5281/zenodo.4732648)
- P24 kernel extension (https://doi.org/10.5281/zenodo.4732909)
- P31 kernel extension (https://doi.org/10.5281/zenodo.4733071)
- P32 kernel extension (https://doi.org/10.5281/zenodo.4741503)
- P33 kernel extension (https://doi.org/10.5281/zenodo.4743117)
- P34 kernel extension (https://doi.org/10.5281/zenodo.4743309)
- P41 kernel extension (https://doi.org/10.5281/zenodo.4743733)
- P42 kernel extension (https://doi.org/10.5281/zenodo.4743866)
- P43 kernel extension (https://doi.org/10.5281/zenodo.4744032)
- P44 kernel extension (https://doi.org/10.5281/zenodo.4744080)
The latest version of the database encoder (https://github.com/masasaito/TAMUoic2019)

6. Requirements

The lead developer, Dr. Masanori Saito encourages the research community to utilize the TAMUoic2019 database for ice cloud studies involving horizontally oriented ice crystals. The only requirement in regards to utilizing the TAMUoic2019 database for research is to acknowledge our contribution in your papers/presentations by:

cite Saito and Yang (2019) in a relevant section of the main text.
add the following description in Acknowledgement section or Data Availability section: "The scattering properties are obtained from TAMUoic2019 (https://github.com/masasaito/TAMUoic2019).".

7. Frequently Asked Questions

For what applications the TAMUoic2019 would be useful?

As oriented particles induce a strong specular reflection at a specific solar-viewing geometry, the TAMUoic2019 database is expected to be useful for 1) lidar radiative transfer and remote sensing applications; 2) total and polarized reflectance simulations; and 3) optical phenomenon simulations associated with ice clouds. For more information in example applications based on the database, see Saito and Yang (2019).

What particle size definition is used in the database?

The TAMUoic2019 Version 1.1.0 uses "maximum dimension" (defined as a longest axis of a hexagonal column/plate) as the size definition.

8. Developer's Log (v1.0.0 or above)

Version 1.2.0 (Planned)

Incorporate tilt angle PDF specification into the encoder.

Version 1.1.0 (04/24/2021)

Implement the kernel technique and split into data kernel and encoder. This reduces the total data size (1.8TB in v1.0.0 to 500GB in v1.1.0).
Improved a user interface, allowing a user-specidied bin intervals for the maximum dimension, wavelength, and incident polar angle.

Version 1.0.0 (07/10/2019)

The TAMUoic2019 database with an ASCII format is published and available upon requests to the authors.