Dr. Emilya Nurjani Profile

Dr. Emilya Nurjani

at Univ Gadjah Mada

SPIE Involvement:

Author

Publications (3)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 22 December 2021 Paper

Analysis of convective cloud presence surrounding whirlwind events in Yogyakarta, Indonesia

Muhammad Galih Prakosa, Emilya Nurjani

Proceedings Volume 12082, 120820E (2021) https://doi.org/10.1117/12.2617507

KEYWORDS: Clouds, Humidity, Java, Meteorology, Thermography, Infrared radiation, Infrared imaging, Analytical research, Spatial analysis, Satellites

Read Abstract +

Whirlwinds are a meteorological disaster that often strikes Indonesia's territory, including the Special Region of Yogyakarta on Java Island. The formation of this small-diameter vortex of rapidly spiraling air depends on the presence of convective clouds, particularly Cumulonimbus (Cb). This research was intended to analyze the spatiotemporal distribution of convective clouds in the region according to whirlwinds recorded in 2019. The research used historical data consisting of the dates and locations of whirlwinds throughout 2019 to determine their spatial distribution. For this purpose, Himawari-8 images with bands 13 (IR1) and 15 (IR2) captured on said dates were processed using the split windows technique in SATAID software. Other data like daily synoptic weather, landscape, topography, and land use were also analyzed to provide atmospheric and land conditions surrounding the weather events. The analysis results showed convective clouds, especially Cumulonimbus (Cb), were present on every date of the event with various distribution and massiveness and always appeared preceding the whirlwinds. On March 17, 2019, the most massive convective cloud coincided with three whirlwinds striking Sleman, Bantul, and Kulon Progo. Tropical cyclone Savannah that hit the southern part of Java Island, including the study area, created atmospheric anomalies responsible for this cloud formation. Low air pressure, high humidity, rainfall, level topography, and land used for settlements and rice fields are concluded as contributing to the convective cloud and whirlwind formation in the region.

Proceedings Article | 22 December 2021 Paper

Attenuation correction effects on quantitative precipitation estimation (QPE) at Sidoarjo weather radar

Laode Bangsawan, Retnadi Jatmiko, Emilya Nurjani

Proceedings Volume 12082, 120820D (2021) https://doi.org/10.1117/12.2617901

KEYWORDS: Signal attenuation, Radar, Reflectivity, Clouds, Meteorology, Temporal resolution, Backscatter

Read Abstract +

Weather radar waves experience attenuation due to meteorological objects in their path or referred to as wave attenuation. Attenuation can cause a large enough error to reflect the weather radar as input data for the calculation of QPE through the Z-R relation which eventually also causes an error in the QPE value. Attenuation can occur along the wave propagation path that contains meteorological objects, so that the farther from the weather radar location, the higher the potential for QPE error caused as the consequence of unapplied attenuation correction. Weather radar applies a local Z-R relation model where the backscatter of meteorological objects received by the radar is processed into a reflectivity value (Z) and then processed through an empirical equation to produce an estimated rainfall (R). There has been no research on attenuation correction using the Z-R relation model which was developed in Indonesia to determine the effect of attenuation correction from QPE in Sidoarjo weather radar. This research is intended to apply the attenuation correction preprocessing based on Kraemer Verworn preprocessing algorithm and Z-R relation model processing algorithm, Arida et al., developed in Indonesia for the QPE calculation considering the radius from the weather radar location. QPE that is incorrected for attenuation will be used as a comparison in this study to determine the differences that occur before and after the attenuation correction is applied. Furthermore, validation is carried out with rainfall observations from rain gauges through correlation analysis and RMSE. The results show that rainfall without attenuation correction tends to be of lower value, especially at greater distances from the weather radar. A higher correlation with a lower RMSE is generated by QPE with attenuation-corrected raw data input and at the relatively close distance to the weather radar.

Proceedings Article | 22 December 2021 Paper

Analysis of extreme rainfall distribution and tropical cyclone impact in Yogyakarta, Indonesia

Yossi Veronica Octhreeana Siahaan, Emilya Nurjani

Proceedings Volume 12082, 120820F (2021) https://doi.org/10.1117/12.2617398

KEYWORDS: Meteorology, Climatology, Environmental sensing, Climate change, Analytical research, Satellites, Infrared radiation, Geography, Ecosystems, Associative arrays

Read Abstract +

Extreme weather occurs when meteorological conditions in a specific location are unusually lower or higher than the average pattern, for example, tropical cyclones and extreme rain events. The southern margin of Yogyakarta, a province in Indonesia, abuts the Indian Ocean as one of the active tropical cyclone basins on Earth. Therefore, tropical cyclones potentially affect the rainfall characteristics in the region. This study aimed to ascertain the threshold values and frequencies of extreme rainfall and the impact of tropical cyclones on daily rainfall in Yogyakarta. It used 30-year rainfall data (1991‒2020) from the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) and three methods for determining extremes: the percentile method and two fixed thresholds set by Indonesia’s Meteorological, Climatological, and Geophysical Agency (BMKG) and World Meteorological Organization (WMO). Details on tropical cyclone occurrences were obtained from Australia’s Bureau of Meteorology. The results showed that the 99th percentile made the nearest threshold values to the fixed ones set for extreme rainfall by WMO and heavy rain by BMKG (R50mm). Extreme rainfall occurred in the west more often than in other parts of the province. In 1991‒2020, four tropical cyclones entered the Yogyakarta area, including Tropical Cyclone Cempaka on November 28, 2017, which induced inordinately high rainfall that exceeded the percentile threshold and the WMO’s fixed threshold of 50 mm (R50mm) for extremes and fell in the category Heavy Rainfall by the BMKG standard.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years