Temporal resolution refers to the ability of the ultrasound system to distinguish events occurring closely in time. In color flow imaging, temporal resolution is affected by the frame rate, which can be increased by decreasing the width of the color field of view. This is because a narrower color field requires fewer scan lines to be processed, allowing for more frames to be captured per second.
ARDMS Sonography Principles and Instrumentation guidelines
Edelman, S. K. (2017). Understanding Ultrasound Physics.

Acoustic Shadowing: This artifact occurs when a structure absorbs or reflects most of the ultrasound waves, causing a shadow behind the structure. It does not cause improper positioning of a reflector on the display.
Speckle: This is a form of noise in ultrasound imaging that appears as granular texture. It can affect image quality but does not lead to improper positioning of reflectors.
Enhancement: This artifact occurs when the area behind a weakly attenuating structure appears brighter. It affects the brightness of the image but does not affect the position of reflectors.
Range Ambiguity: This occurs when an echo is received after the next pulse has been sent out, causing the reflector to be placed at an incorrect depth on the display. This is because the system assumes the echo came from the most recent pulse.
Reference:
"Ultrasound Physics and Instrumentation" by Frank Miele
ARDMS Sonography Principles and Instrumentation study materials

The Doppler shift is directly related to the cosine of the angle between the ultrasound beam and the direction of blood flow. As the angle increases from 30 degrees to 60 degrees, the cosine of the angle decreases (cosine of 30 degrees is approximately 0.87, while cosine of 60 degrees is 0.5). Since the Doppler shift is proportional to the cosine of the angle, increasing the angle results in a decreased Doppler shift. This means the measured blood flow velocities will appear lower at a 60-degree angle compared to a 30-degree angle.
American Registry for Diagnostic Medical Sonography (ARDMS). Sonography Principles and Instrumentation (SPI) Examination Review Guide.

To avoid exceeding the Nyquist limit and prevent aliasing in Doppler ultrasound, the pulse repetition frequency (PRF) should be increased. The Nyquist limit is half of the PRF, so by increasing the PRF, the Nyquist limit is raised, allowing the system to accurately measure higher velocities without encountering aliasing artifacts.
ARDMS Sonography Principles and Instrumentation guidelines
Zwiebel, W. J., & Pellerito, J. S. (2017).Introduction to Vascular Ultrasonography. Elsevier.

Range ambiguity artifact occurs when echoes from one pulse are received after the next pulse has been emitted, leading to the incorrect placement of echoes at shallower depths than their true location. This artifact typically happens when the PRF is set too high, causing the ultrasound system to interpret delayed echoes as coming from the current pulse rather than the previous one. This results in reflectors appearing closer to the transducer than they actually are.
References:
ARDMS Sonography Principles & Instrumentation Guidelines
Kremkau FW. Sonography Principles and Instruments. 9th ed. Philadelphia, PA: Elsevier; 2016.